Quickly tested it and i sometimes get it too.... so it must have snuck in with the latest changes :(
The stutters are so annoying: i did the instancing thing too a while back, which resulted in the game not respoinding for a few seconds (because i needed to instance a lot of different items per level) and could even lead to a crash on weaker machines. Currently im trying to just let the ResourceLoader load everything needed in the background before it gets used. This seems to work for some people more than for others. My other (weak) laptop runs relatively smooth that way, but a streamer yesterday had visible minifreezes on multiple occasions.
the level loaded but the loading screen didn't fade away and it stayed up
Thats a new one. Just got to reproduce this and it seems to happen if you switch levels while the fading of the loading screen isnt done. Will fix that.
Thanks a lot for reporting these things, really appreciate it!