It does go back into the block, but then it will shoot out again at random, no rhyme or reason. Doesn't matter if something goes inside of it or if it was freshly spawned/rendered. Try spawning a bunch of them and just look at them? It's what happened for me. Tried removing them all and putting new ones in too, bug still occurs.
weirdo
MC-107824
Added screenshots, thanks for reminding me @Marcono1234
It does go back into the block, but then it will shoot out again at random, no rhyme or reason. Doesn't matter if something goes inside of it or if it was freshly spawned/rendered. Try spawning a bunch of them and just look at them? It's what happened for me. Tried removing them all and putting new ones in too, bug still occurs.