Greetings,

A simple curiosity is all.
I cannot supply a 3dm file, and the reason will become apparent.

Try this experiment:

1) draw a solid box on one layer
2) draw a sphere intersecting the box on a second layer
3) boolean difference the two - not keeping objects
4) you should now have a subtracted solid, but appear to have two polysurfaces, one on each layer
5) save file and reopen
6) now you have the subtracted solid, on its original layer

So, now I understand that geometry states may not become static until saved. Got it!

Why?