Anything destroyed with gravity will be gone but brought back next time you launch UEFN
Repro:
Launch UEFN and Live edit
Place in live edit some construction that has gravity
Delete its support
All props will be deleted.
Restart UEFN
Props will be there
uefn-attachments-2022.10.09-18.40.44.zip (4.6 MB)
Also issues related to this: