When you break the top part of a door in creative mode, it will drop, but not if you break the bottom part. (Idk if it running 1.16.210 or 1.16.220.51 beta btw).
MCPE-121090
Doors in creative mode
Resolved
Duplicate
0
...
(Unassigned)
Unconfirmed
iOS
1.16.210
Retrieved
Duplicate of MCPE-104226