I can assure you that we haven't made ANY adjustments to the screen in this update or any of the recent ones either. The most likely reason why you're seeing black crush now is because
You're looking for it
This batman clip has hard compression which increases black crush
You might be viewing it in a darker environment now that you're looking for it than what you normally use your phone in
Maybe you've been mostly watching in 60hz before as lower frequency has always had less black crush.
Memory (unless you're blessed with photographic memory) can never be trusted and most people have a tendency to remember what they want to remember
I'm going to close this thread as there's no point discussing this any further. I hope you understand. Thanks!