piko's running up/coming down from chopped trees

hello! there seems to be a bug where a piko will run up and spawn from a chopped tree if you leave the stump, though they dont seem to spawn if you dig the stump up. it's kinda unfair but still funny when they steal something and disappear up an invisible tree.

another thing with the pikos is, if you scare them up a tree, they dont ever come back down? even when i left and came back, none of the piko's had reemerged from their trees. 

thank you, i hope this helps!