Dork Age/Anime and Manga

Anime series in general tend to hit Dork Ages when the anime overtakes the manga and, as a result, goes into a Filler Arc.
Once Yoshida Reiko left the Tokyo Mew Mew project, Ikumi Mia tried to write a sequel incorporating the retcons made in the TV show and replacing Ichigo with a new character named Berii. Ichigo herself lost her powers except as a living accessory to the new heroine, her origins and family life were completely ignored in favor of sending her to Europe, and she became a washed-up hero. It's no surprise Tokyo Mew Mew a la mode has a high degree of Fanon Discontinuity amongst fans who also really dislike Berii.
For some portion of the fanbase, Magical Record Lyrical Nanoha Force has becoming this for the main continuity of the franchise.
Bleach entered this with The Lost Agent arc, with a new set of characters we've never seen before, whole new kinds of powers, a plot that is almost completely unrelated to everything we've seen before, and the overall feeling of the filler arcs from the anime.
- To be fair, all the new stuff got added because just about every big plot point up until got resolved except for two, the fact that Aizen's still alive, and Ichigo losing his Shinigami powers. One of them is being handled in this arc, and the other one fans do not want to show its face again for quite a while.
Lupin III has the pink-jacket era, which consists of the third anime series and the Legend of the Gold of Babylon. Both the series and the movie had Lupin wearing a pink jacket, most of the adult themes downplayed and the slapstick brought Up to Eleven. Today, it is widely ignored by both the anime producers at TMS Entertainment and most fans in general.
Depending on who you ask, the whole anime industry between 2008 and 2012, due to the convergence of the popularity of Moe series pandering to the Otaku demographic, the increasing in piracy, the diminution of interest on anime and manga from Western fans (as many of the new productions of the era didn't appeal to western sensibilities), and the subsequent disinterest of Japanese for licensing their proprieties abroad while milking their local market for what it was worth. The popularity of streaming services like Crunchyroll and Netflix, which made licensing costs more feasible and give the licensers more control over their production's international broadcast, along with new anime and manga series who have a more universal appeal, are bringing the industry into a resurgence; time will say if this sustains.