It s a small issue - but an annoying one:
There are a few commands, that do not create the new Objects on the current layer, but on the ones of the input object.
_mesh
_toNurbs (for SubD)
_booleanUnion (Delete Input = No)
this got reported already at several topics.
for example:
but let s collect all commands, that do not create a new object on the current layer !
@Gijs you may want to add above issue to your Inconsistency list)