D2r weirdness, anybody experienced similar?

Yesterday installed the d2r back as I felt like playing d2.
Game worked fine, everything maxed out in settings for quality.

Today, nothing has changed or touched, hop back in and suddenly the game constantly drops fps. I couldnt find any reason to it.

Anybody experienced something similar?

Specs:
Rtx 4080
i7 16 cores
16gb gddr5

EDIT:
Repaired files and the issue was gone.
Seriously, do I have to repair files every time before I want to play again? come on Blizzard, try at least.

EDIT2:
It does seem that way. I can join in after repair and it runs fine smoothly again, but once I close the game and come back later → its back to lag / stutter mode. Its still playable, but very annoying. Id rather just repair the files, but its a bit weird that this is fixing it and required.