After spending some time in engine - the problem is solving by itself (I don’t know how), but I want to understand why does it happen and how to fix it?
This is very likely texture streaming. The performance of texture streaming can be configured with some console/rendering variables (giving it more memory) and/or marking certain textures as higher priority or pre-load.
I disable it but nothing have changed. Or I need to restart engine?
Update: I restarted project a few times and didn’t see problem again. Seems like you was right. Thank you!