This is a new issue, this never happened in Creative. When you multiselect pieces with no structural integrity and pasted them, they copies also didn’t have it. Now in live edit, in latest update, pasting a multiselection of pieces that don’t have structural integrity will re-enable it, which makes it a VERY DESTRUCTIVE BUG, as the moment you delete a piece or move it, the full multiselection just collapses, even if it wouldn’t collapse before it was duplicated.
Repro:
-Build a scene using building pieces that have no structural integrity
-Open live edit
-Multiselect the pieces and place them in the air
-Delete one