When you put tuff bricks or polished tuff blocks in a stonecutter you cannot change the variant to stairs, slabs or walls. So you can only make the variants from the original tuff blocks
MCPE-179057
Tuff variants unchangeable in stonecutter
Resolved
Duplicate
0
Actually, nevermind about my previous comment, can confirm in 1.20.70.24 Preview. It can also considered as a parity issue because Java Edition didn't have this problem.
Edit: Duplicate of MCPE-176613.