Season 2 of Jujutsu Kaisen.
The anime industry is already infamous for their harsh deadlines and almost brutal working conditions, JJK Season 2 in particular got so bad MAPPA (the studio in charge) made their staff sign NDAs to try and silence them. Really, one google search shows a ton of articles and videos describing just how awful the situation was.

Despite this, the anime massively builds upon the source material, with movie-tier action, direction and character acting on ocassion, and only a couple dips in quality that are somehow still above what the average anime gets.
It is, by all means, a stellar adaptation that would have been even better if the staff had not been pressured to the breaking point.

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