Cave-in when cut down mush trees

[yagogoii]

there was a patch makes mushroom tree wont cause cave-in when cut down.
but when i hit a tree out of my mine today ,cave-in strike me and my horse.
it is a bug ,or design to?
and i planted some mush at lv 5 for tar kiln ,how can i remove them safely?

[Granger]

Cave-in was changed from always been caused on the tile of the support to cave in unstable tiles no longer supported by anything.
Possibly you removed the last support that was holding an unstable tile?