Channel Hop: Technically averted; ABC aired both the original series and will air the upcoming reboot in 2021. However, the original series was produced by New World Television, while the latter is an in-house production via 20th Television (who folded New World, taking The Wonder Years with it, and was eventually bought out by ABC parent Disney).
Dawson Casting: Largely averted for the main cast. One notable exception was Julie Condra, who guest-starred as a high school freshman at age 20. This made the story arc where Condra's obviously older, sexually mature character comes on to innocent young Kevin Arnold rather jarring.
Fake American: Olivia d'Abo (who was originally from the Paddington area of London). You know, Karen Arnold. Wait... you did remember that Kevin and Wayne have an older sister, didn't you?
Germans Love David Hasselhoff: The series was pretty popular in Mexico during its broadcasting tenure, to the degree that many of their voice actors had become celebrities (especially Kevin's younger and adult versions and Winnie's Mexican voice actors).
Keep Circulating the Tapes: Was this for a long time, due to the large amount of hit songs featured in the show, and the corresponding legal and financial snags involved with licensing the rights to all of that music.. Netflix and Amazon eventually secured streaming rights, but these still have edits to the soundtrack that include soundalikes and even an alternate version of the theme. In October 2014, Time Life/StarVista Entertainment released the complete series with the vast majority of the licensed music intact, and individually-released seasons have followed.
Missing Episode: The first of the show's two clip shows is not available for viewing on Netflix.
Romance on the Set: In the Mexican Spanish dub, adult Kevin and Winnie's voice actors were married.
The Other Darrin: Arye Gross narrated the pilot; Daniel Stern narrated the series. The pilot with Gross' narration aired only once (following Super Bowl XXII); all airings after the original broadcast replaced Gross' voice with Stern's.
Throw It In!: Dan Lauria revealed in an interview that Fred Savage improvised the bit in "My Father's Office" where Kevin mimics Jack's grumpy behavior upon returning home from work.