Summary:
When you pick block a cauldron, it gives you a separate item for the cauldron.
The problem doesn't exist in 1.20.51 - you get the normal cauldron item there.
Steps to reproduce:
Place the cauldron.
Pick block on cauldron.
Observed results:
Pick block on cauldron gives you the "technical" cauldron item.
Expected results:
Pick block on cauldron gives you normal cauldron item (as in 1.20.51 and below).
Video:
https://drive.google.com/file/d/1F0ObwWPW6KVt2LQqw7guJMJfnfyJfjI6/view?usp=drivesdk
Seems fixed as of 1.20.70.24 Preview, relates to MCPE-179063.
13/Mar/24 edit: I still can't reproduce this in 1.20.70.