Author Existence Failure: Yasuo Yamada, the voice of Lupin the Third, died of a brain hemorrhage in 1995, a month before the release of Farewell to Nostradamus, the movie that would mark the series' return to the big screen in ten years. Fortunately, his will stated that, if he were to pass away, the baton should be passed to Kanichi Kurita (a popular comedian and impersonator), who voices Lupin from that movie onwards. In honor of Yamada, a message was placed at the end of the film's credits: "To Yasuo Yamada, Eternal Lupin the Third: Thank you!".
The replacement of the original cast with the above-mentioned actors came about due to budget troubles at TMS and caused quite a bit of angst. TMS wanted to do an OVA with movie-quality animation, but couldn't do that and still afford the original five actors (who were, at the time, the highest-paid seiyuu in Japan) on the budget provided.
This ended up causing a rift between Monkey Punch and Yasuo Yamada, as TMS had asked Monkey Punch his opinion on replacing Yamada. His answer was actually a noncommittal "I may not like it, but it's your show; I really can't tell you what to do." Unfortunately, through Poor Communication Kills, it was finally relayed to Yamada as something akin to "Go ahead and fire him." Even though Monkey Punch, who had fostered a good working relationship with Yamada tried personally to smooth things over (and even though the experiment of replacing the main Lupin cast was deemed a catastrophic failure), their relationship remained strained until Yamada's death in 1995.
Missing Episode: Series 2 Episode 3, "Hitler's Legacy" (a.k.a "To Be Or Nazi Be"), was this for a while with the series' US release, as [adult swim] refused to air it for pretty obvious reasons and Geneon withheld it from the Volume 1 DVD. It eventually appeared in Volume 5 (at the end of the first season).
Worth noting that Geneon's decision to withhold the episode (even with their saying from the beginning that it would be included, just on a future volume), caused a massive backlash among the preexisting Lupin fanbase. Cries of "censorship" and Ruined Forever abounded, and may have helped torpedo the series's chances in North America (again).
No Export for You: For a very long time, the only place outside Japan to see the 1971 "Green Jacket" TV series was Italy. North America finally got it in 2012.
The third TV series ("Pink Jacket") has never been legally seen outside of Japan. In fact, the only product of that era to make it to foreign shores was the Legend of the Gold of Babylon film.
Of the 20+ annual Lupin TV specials produced to date, only 9 so far have made it to North America.note Those would be the 1993-2000 ones – "Voyage to Danger", "Dragon of Doom", "The Pursuit of Harimao's Treasure", "The Secret of Twilight Gemini", "Island of Assassins", "Crisis in Tokyo", "The Columbus Files", and "Missed by a Dollar" – all of which were picked up by Funimation; plus 2002's "Episode 0: First Contact", picked up by Discotek Media.note The specials that have NOT made it to North America include the first four – "Bye Bye Liberty Crisis", "The Hemingway Papers", "Napoleon's Dictionary", and "From Russia with Love"; 2001's special "The Alcatraz Connection"; and everything from 2003 onward – "Operation Return The Treasure", "Stolen Lupin", "Angel Tactics", "Seven Days Rhapsody", "Elusiveness of the Fog", "Sweet Lost Night", "Lupin vs Detective Conan", "The Last Job", "Blood Seal ~ Eternal Mermaid", and "Record of Observations of the East ~ Another Page". In addition, the "Return of Pycal" OVA remains unlicensed.
All but two episodes of the second half of the "Red Jacket" series (episodes 80-155)note Episodes 145 and 155 were released by Streamline in the 90's under the title "Tales of the Wolf", remain unavailable in the West.
The Other Darrin: With over forty years of animation and dubbing, it is inevitable that examples of replacements without In-Universe explanation occur.
The Japanese cast for Lupin is remarkable for its extreme consistency over many decades. However, even it has had its shakeups...
Lupin III Pilot Film, the original 1969 pilot film (shot and recorded twice) Other Darrin'ed itself, by having two completely different voice casts. Strangely, Goro Naya (Zenigata's long-time VA) played Goemon and Chikao Ohtsuka (Goemon in the first series) played Zenigata. The only other actors from these recordings retained for future Lupin projects were Eiko Masuyama as Fujiko and Kiyoshi Kobayashi as Jigen.
In 1987, The Fuma Conspiracy was produced on a tight budget, so TMS decided to replace the principal cast (at the time, the highest-paid voice actors in Japan) with cheaper actors. Thus, Lupin is played here by Toshio Furukawa, Jigen by Banjo Ginga, Goemon by Kaneto Shiozawa, Fujiko by Mami Koyama, and Inspector Zenigata by Seizo Kato. Fan reaction was... less than positive, and TMS switched back to the original actors for the annual TV specials that started not long after. Contrary to rumors at the timemada, Monkey Punch had nothing to do with this one.
Lupin's longtime voice actor, Yasuo Yamada, was smart enough to know that he wouldn't be sticking around forever, so he personally trained and handpicked a friend of his, comedian Kanichi Kurita, to succeed him as the voice of Lupin should anything happen to him. Prescient, as Yamada unexpectedly passed away shortly after this, in early 1995. Kurita has voiced Lupin in everything since.
In 2011, TMS retired Makio Inoue, Eiko Masuyama, and Goro Naya (Goemon, Fujiko, and Zenigata, respectively), replacing them with (much) younger actors from the 2011 special onwards – Daisuke Namikawa as Goemon, Miyuki Sawashiro as Fujiko, and Koichi Yamadera as Zenigata.note The original cast would reunite one last time in 2012 for a ten-minute short, Lupin Family All Stars, a few months before Naya's death. This leaves Jigen as the only character of the main cast whose seiyuu has remained consistent since the 1969 pilot short film (not counting The Fuma Conspiracy).
Lupin's English cast has never been consistent with several media being dubbed and redubbed multiple times, due to several failed attempts to successfully market the franchise in the English-speaking world over the years. One movie (The Mystery of Mamo) has had four dubs produced between 1979-2003. To date, at least seven different English Lupin casts are known to exist.note For reference, those casts are Streamline (Los Angeles – Mamo, Cagliostro, Tales of the Wolf), AnimEigo/Coastal (North Carolina – Fuma only), MangaUS/Animaze (LA, Cagliostro only), Geneon/Phuuz (LA – Red Jacket and Mamo), Funimation (Texas – Eight TV specials, Nostradamus, Dead Or Alive, and the Fujiko Mine series), and the dubs by Manga Entertainment UK (Mamo and Liberty Crisis) and JAL (Mamo only). Despite three different LA-based studios recording and rerecording parts of the franchise, there are no consistent voices between any of them.
In an inverted Other Darrin, Richard Epcar has worked for the Manga/Animaze, Geneon/Pioneer, and Funimation casts... playing Goemon, Jigen, and Inspector Zenigata, respectively. Fans joke that the next role he's being considered for is... Fujiko!
After Lupin VIII was scrapped, DiC had to come up with something to replace it (they had already committed considerable capital to the project). They ultimately created Inspector Gadget. TMS even helped animate the first season.
The Lupin VIII pilot has been released on the as-of-now Japan-exclusiveLupin III: Master File collector's DVD, with subtitles derived from the pilot's original script.
Bob Bergen (the voice actor for Lupin in Streamline's dub) auditioned for Geneon's dub of the second TV series, but ultimately was not able to get the part as it turned out to be a non-union production.