Steps to reproduce:
Obtain a flower pot
Try to place it on any leaves
Observed result:
You can't.
Expected result:
You can.
Original description:
Summary: Flower pots can't be placed by hand on top of "thin" blocks and leaves but can be placed using the setblock command which is not survival friendly.
Steps to reproduce: Place end rod, iron bar, chains or leaves then try to place a flower pot on top of it, it wont place it.
Related issues
is duplicated by
Comments

Flower pots can be placed on iron bars, end rods and chains as of 1.21.2, however, they can still not be placed on leaves.
In Java Edition 1.13, it was updated so that flower pots no longer require support and can be placed on any block, as detailed in MC-127036. Implementing this change on Bedrock Edition would address the issue.