I had this issue today while doing a stream. Occasionally the stack insreters on my low density structure assemblers would just sit around and shake. The workaround fix was just eliminating the underground belts where I could. I happened to be recording the session. Right here

HAH! I came here to tell y'all that you fixed it on the subreddit. You guys rock! Thank you so much!

Unfortunately, the issue is affecting all of the autosaves for this map.

New games work. Other save files work.

I've restarted the game and my computer. I'm running Windows 10 Home.

I'm running the vanilla game.