[2020] Sudden fps drops

I was playing Rainbow 6 Siege yesterday at 144fps stable with not even 1 fps drop at all. Today I logged on and I can't even get 144 fps. The highest I reached was 112 fps.
I haven't changed any settings whatsoever (I play on lowest settings), I haven't done any updates on my pc or anything that could be related.

I don't understand how this happened. It started to happen the first game I played with the new hub/menu background (Osa in the background)

Note: I know 30 fps might not seem like alot but I've been playing on 144fps for a good while and my eyes can somehow see the difference + the fact that my fps aren't stable. Going between 80 to 112.

Specs:
CPU: I5-10600K
GPU: RTX 2060
RAM: 16GB
My temps are fine, 50-60C ingame for both GPU and CPU.
My usage is also fine, 50% CPU usage and 25% GPU usage in game.

EDIT: This game is stupid, I couldn't reach 144fps on the lowest settings, I verified the game files, updated my graphic card driver and now it runs at 144fps on ultra.