I got this issue several times in single player, while trying to design a nether sprout/root farm. My assumptions are that It's either entirely triggered by rng or by the nylium blocks being moved at unfortunate times and chance.
Expected behaviour:
Nether vegetation grows normally around block it's being dispensed on or if blocks are in movement, nothing happens.
What happens sometimes instead:
Vegetation doesn't appear, server tick freezes, client continues like everything is normal. (So I can still fly around, but can't flick levers, pick items up or quit & save the game. (On quit the dirt background shows up, but nothing happens after that, can't close it with alt+f4 but the window doesn't show up as 'not responding'))
How to reproduce:
Use bone meal on nylium block with upward facing dispenser while the nylium is being moved by a piston. (Not sure if piston movement or dispenser direction matters)
Linked issues
is duplicated by 1
Comments 4


Confirmed for 20w13b.

Confirmed. The server completely freezes, so does the TPS graph on the lower right. Easy reproduction steps can be found in MC-175328

Same underlying issue as MC-171020 (twisting vines spawning over void), no longer reproducible
Works when using bonemeal by hand, too.
Doing this in single-player prevents debug crashes from working properly (see MC-175328).