Huge frame rate drop in LESS intensive levels during stream

Hello,
I’m about to release a demo of my game on 4.27. it’s an open world game with a lot of stuff that streams into a persistent level but you can go inside places that open much smaller, separate levels. (like stores, etc)

usually in the large world I get 50-60FPS and in the smaller maps I get 100+…but by default vsync is on, though, so I usually get an average of 50-60FPS everywhere.

during a stream of an early release in the open world everything ran fine…as soon as the player entered one of the smaller maps there was a massive drop to around 1FPS…obviously this is the opposite of what i would expect. There is barely anything in these smaller levels. the game is fairly low-res/low-poly and I reduce it to 720p to get a more retro look.

I’m not able to produce this problem on any machines I have.

Does anyone have any idea where I could even start trying to solve this issue?

Thanks for any help!