https://youtu.be/vvTCpOL7CSg

I was making an iron golem farm in a creative 1.16.1 flat world.  I tried to deal with the cats by placing a campfire in the 1x1 chute in the middle.  Then I crouch placed a sign on top of the campfire and attached other signs to that to hold up the lava blade for the iron golem.

When I exit the world and then restart it, the signs all break and the lava flows everywhere.  Perhaps it's something to do with the campfire "starting" when the world starts?

I tried repeating this by active chunks i.e., teleporting away / moving away outside the simulation distance, but no effect.  It's only when the world starts.

Not sure if it's a bug, or intended.