Sometimes, characters develop over the course of a show. And sometimes, shows will present new scenes from earlier time periods. And sometimes, characters in a flashback will exhibit character unlike the way they acted before the time the flashback is occurring.
For example, when Bob started on the show in 1991 he was characterized as a Jerkass, but became a Jerk with a Heart of Gold in 1993, and then just became a nice guy by 1995, but is shown in a recent flashback to 1990 to have been a Nice Guy in 1990, with no explanation/extenuating circumstances.
Usually, this happens unintentionally due to Flanderization and Characterization Marches On, often due to the too many flashbacks to track characterization in an Expansion Pack Past. This might be used to Retcon an existing flashback, maybe because it also had to be reshot since it was a Flashback with the Other Darrin. If you not only pick up your old characterization but also your old visual style, it's a Retraux Flashback.
Trope name comes from "backporting," a concept in software development where features from a new codebase are imported to an older branch of development.
- In One Piece we have Luffy, the straw hat wearing hero. He got the hat, which is his #1 Dime, as a 7-year-old. At the start of the series, where he is 17, this caused a problem for him because the hat would often fall off in battles so that he would have to make another person hold it for him. After the Alabasta arc, he gets a string strap for it so that he can have it hanging from his neck while fighting which gives him much more flexibility (probably because he was very close at losing the hat in the Alabasta arc). Some time later, we get a flashback to when he was 7 years old, and suddenly, it appears that he already had the string strap back then.
- Whenever Ash appears in flashbacks he is an excitable Friend to All Living Things and an all-around Nice Guy. This is ignoring his personality in the Original Series (Kanto and Johto) where he was more of an Idiot Hero, had more aggressive traits, and was stubborn. It was his Character Development that transformed him into a more gentle character by Sinnoh.
- One episode also has Pikachu suffer amnesia, but still act kind-natured and naive, despite the fact that Pikachu started off a disobedient lazy Jerkass when Ash received him in the first episode.
- Judge Anderson, a psychic Judge in the Dreddverse, was a very flippant and easy-going character when she first appeared in Judge Dredd, though would get serious when the situation mandated it. As time went on, she became a rather serious character most of the time, and her dominant mood was vague despair at the shape of the world. In late 2010, possibly as part of the buildup to the new Dredd movie, Alan Grant started writing a prequel series, Cadet Anderson, set during Anderson's days as a cadet. In the prequel series, she is a very serious character who wishes the world could be better, in seeming contrast to the fun and light-hearted lady who first fought Judge Death.
- General Sam Lane, originally Lois's gruff father who didn't like Clark much and wasn't entirely impressed with Superman, but had a good heart beneath it all, died during the alien invasion of Our Worlds at War. When he came Back from the Dead, his experiences in that war had left him with a new anti-alien attitude that turned him into a General Ripper declaring war on New Krypton. In the Superman: Secret Origins miniseries, Sam was gunning for Superman from the first moment he learned Metropolis's new hero was an alien, and is responsible for creating Metallo as his anti-Kryptonian weapon.
- In Star Trek: Nemesis, they show a picture of Jean-Luc Picard when he was young, and for some reason, he was bald, despite the fact that his balding had everything to do with his age, as previously shown in the show. This also makes the villain quite baffling. However, Patrick Stewart himself really had lost his hair by this age, really muddling things. One handwave that swims dangerously close to being a Voodoo Shark is the fact that both the picture and Shinzon have stubble, indicating both the young Picard and his clone shaved their heads on purpose. Other flashback Picards with hair had just let it grow back.
- The Big Bang Theory: In the flashback episode "The Staircase Implementation," Sheldon acts like his current, flanderized self instead of his more socially conscious earlier persona, despite the fact that the episode takes place four years before the series begins.
- Frasier: Martin was supposedly insufferably crabby and unpleasant before Frasier moved back to Seattle, which is used to explain why Frasier rarely visited when he lived in Boston. Flashbacks in some later seasons definitely show family tension, but Martin’s personality isn’t noticeably different (he’s even apologetic for what little crabbiness he displays), making a lot of the pre-series family drama a mostly Informed Flaw.
- Averted in Lost, which cuts around with its flashbacks, but keeps characterization as established when the scene takes place (noticeably when Shannon and Boone are shown shortly around the time of the crash, Shannon is still doing nothing but complaining.)
- Series VII of Red Dwarf contains flashbacks to shortly after the revival of Rimmer (Series I). The style of the 'H' on his head and his uniform were the ones from Series VII.
- Kryten's changed appearance is handwaved by the explanation that Lister rebuilt him after a spacebike crash, yet a few episodes later we see a moving photograph of Kryten pre-crash and he looks (and speaks) the same as post-crash. Additionally, the other Series 4000 mechanoid we meet, Able, looks like the "rebuilt" Kryten as do his spare heads in "DNA" and "Beyond a Joke".
- The flashback in series 2's "Stasis Leak" to before the accident maintains the set design and props that were added to the bunk room in series 2.
- Highlander the Series: In the pilot, it is stated that Duncan has remained "out of the Game" for over a century. Later, throughout the series he is depicted in flashbacks defending himself from other Immortals and taking heads throughout said century.
- My Name Is Earl had this twice, both with heavy lampshades. Two flashbacks saw Earl being the good guy despite the show's entire premise being he was an awful person until he "discovered" Karma. One featured Earl saving Joy from a killer bee while his cousin cowered in a tent, and the other was his reasoning for raising two kids who were not his own. Both were described as the only good thing he did before he made the list.
- Star Trek: The Next Generation had this in the series finale.
- The captain's chair shown in the past is the same one as the then-current chair, with little lights under the arm-rests instead of the folding panels the first season chair had.
- Past Worf's makeup design was slightly modified from the current version rather than being the version from the beginning of the series (which took much longer to apply and was more uncomfortable for the actor).
- BIONICLE contains an enforced example. Originally, the race of diminutive villagers was called "the Tohunga" until Maori activists sued the LEGO Group for trying to trademark words in their language. The Story team wrote a scene to change around a few names, with the Tohunga becoming "the Matoran" in celebration of their newfound unity. That was until the story expanded beyond the island of Mata Nui with a Prequel arc. Since they certainly couldn't reuse the old names, the name "Tohunga" was retconned out, and the villager we of the Matoran race from the very beginning.
- Sonic the Hedgehog:
- In Sonic Adventure 2, there are numerous cutscenes which show Shadow fifty years ago. Throughout the game, he acquires numerous bits of equipment, and the items you've got are visible on his character model even in the flashback cutscenes.
- In the first Sonic Adventure game, Tails and Amy have flashbacks dating back to the times of the classic Megadrive games. In them, Sonic, Tails and Amy are depicted in their modern designs. The devs apparently didn't feel like making alternate models for a few seconds worth of footage. This wasn't really a problem until Sonic Generations came out and established that the characters used to look like their classic designs in their younger years, though.
- Soulcalibur: Broken Destiny's version of Yoshimitsu strongly resembles his Tekken 6 appearance, where he looks like an alien rather than a samurai which is what he's supposed to be in the Soul series (it takes place centuries earlier). In the first Tekken, Yoshimitsu looks more like a knight, which is more consistent with how he would have looked when the Soul series is set. Justified by the fact that the Yoshimitsu in both series are separate individuals bearing the same name. As theorized for years and finally confirmed in Soulcalibur V (which included a "Yoshimitsu the Second," the successor to the Yoshimitsu in the preceding four games), the leader of the Manji clan is whomever has ownership of a particular sword, also named Yoshimitsu, which is earned by defeating the previous Yoshimitsu in a Duel to the Death and assuming their name, allowing the cursed katana to accept them as their rightful wielder. The new Yoshimitsu then adopts the mannerisms, fighting style, and identity of their predecessor, thus continuing on the folk legend of Yoshimitsu. Beyond this, Yoshimitsu's design almost always changes between games (Tekken Tag Tournament is the only exception to date, reusing his T3 attire), and quite drastically. Even in his Soulcalibur appearances, where he conforms to a samurai-influenced aesthetic, does Yoshimitsu look wildly different between games.
- Averted in Crisis Core: Final Fantasy VII, where despite having undergone Flanderization in sequels and spin-offs, Cloud acts really close to his original characterisation (or at least as close as you'd reasonably expect considering how much younger he is). Aerith also returns to being bossy and intelligent rather than being Incorruptible Pure Pureness and Yuffie goes back to being sneaky, sarcastic and manipulative rather than a goofy Genki Girl.
- Portal 2 changes the design on many items such as the elevators and the Material Emancipation Grills, yet when you return to destroyed areas from the first game they are fitted with the new design. Visiting "Old Aperture" later on reveals that these new designs were apparently in use in test chambers from decades before the first game took place. The devs specifically avoided this with the original, burn-marked but intact Companion Cube, though.
- Mario & Luigi Superstar Saga + Bowser's Minions updates the standard Mario characters and species to resemble their equivalents in later RP Gs, leading to things like the Toads being made into mere palette swaps and quite a few monsters being given designs based on the main series rather than the original game. It also brings over the Elite Trio and Dr Toadley from Bowser's Inside Story too, opening up a few plot holes in the process (the former are wearing outfits that mark their promotion in Dream Team, latter apparently never met the Mario Bros before Bowser's Inside Story).
- The recent Mortal Kombat games are guilty of this; MK 9's story picks up right after the previous game (Armageddon) but the characters all look as they do when we rewind and go back to the first tournament (Johnny has short brown hair rather than the longer blondish hair he had at the time, Sonya wears her black leather outfit and has her hair in a long ponytail instead of wearing a bomber jacket and having her hair shorter, etc). And Mortal Kombat X flashes back to the MKII part of MK 9 and the characters look as they do in MKX rather than MK 9!
- Solid Snake in the original Metal Gear Solid was extremely buff, but relatively compact, suiting someone who did have to crawl through air vents as part of his job description (his body was modelled on Jean-Claude Van Damme). In Metal Gear Solid 2 he has a thicker physique, which was intended to indicate him ageing from early 30s to middle-age and putting on weight. In Metal Gear Solid 3, his father Big Boss is buffer still, compared in the casting sheet to an Arnold Schwarzenegger type. Several later appearances of the character outside of the core series buff up Solid to his father's level, such as his appearance in Super Smash Bros. Brawl, and his frighteningly muscular render for The Legacy Collection where his biceps are significantly thicker than his entire head.
- When Mr. Freeze was cloned in Batman Beyond, he was depicted as still being bald despite having hair when we see a pre-Freeze Victor Fries in Batman: The Animated Series — though considering the clone later redeveloped Freeze's inability to tolerate warm temperatures, maybe it was a sign of Clone Degeneration.
- Batman: Return of the Caped Crusaders, a tie-in movie to the '60s Batman show, has a mention of Alfred as having worked for the Waynes since Bruce was a child. However, this was an idea introduced post-Crisis on Infinite Earths with Batman: Year One, which was around 20 years after the show ended, and pre-CoIE, Alfred only joined Bruce's employ after Dick Grayson became Robin.
- Try to remember an event from a long time ago and see if you can picture the people involved as they looked then instead of now. Unless you have a Photographic Memory it's unlikely you can.