The composter and cauldron block on the Bedrock edition doesn't use the correct texture when fancy graphics are on. Composter's problem was its inside. The outside was fixed but the inside still does not move on to the bug. Whilst the cauldron doesn't use the proper shade at all on both of its outside and inside.
Here are some screenshots:
I think the cauldron is missing fancy graphics. See MCPE-43583.