Lag at start of game

Unity Engine
1

We have a nature scene with a free flight camera running on WebGL 2.0, Unity version 2021.1.20f1.
The game runs at really well fps wise, but after the scene has loaded, the game stutters/freezes as you turn around to look at stuff. Once it settles down, it runs fine, with the odd stutter every now and then.
I get around 120 fps most of time.
If I reload the scene after it has settled down, I don’t get stutter at start.
I have tried deleting everything in the scene with minimal effect on the stutters (although it does improve slightly). Does anyone know why this might be? Or how to solve it?

Thanks

PS it seems notably worse on Mac browsers Brave and Firefox. Windows Chrome seems to be the best currently.

2

Update: It turns out the lag is caused by having GPU instancing turned on in the materials. Anyone have any knowledge on why that might be?

3

We are aware of this issue and a fix is in the works. I’ll see if I can find an issue tracker link!