Stone, dirt, and leaves can appear inside Woodland Mansion

Is it just in the pumpkin rooms you find a stone block? Both screenshots show pumpkin rooms.

I guess so, I think it's only on pumpkin rooms

I've updated the summary to include dirt and leaves based on my own experience. Java Edition has the same issue (MC-228163) but I don't see it reported for Bedrock yet.

Could you give some examples of seed and coordinates where this occurs in 1.18?

I don't see any stones in pumpkin rooms too much now, but I see more leaves inside.

Leaves
Seed: -1412725903
Coord: 5723 89 1582

Sometimes on roaming in the other world, I can find dirt inside the mansion

& we can find grass blocks in prison cells 

Confirmed in 1.21.44