This pertains to a basic setup that consists of a comparator with a regular block behind it and a filled cauldron further behind.

What I expected to happen was...:
For the comparator to turn off if the filled cauldron was pushed away with a piston.

What actually happened was...:
The comparator stayed on.

Steps to Reproduce:
1. Place a comparator, then a regular block behind it, then a filled cauldron behind the block. The comparator should turn on.
2. Place a piston to the side of the filled cauldron and activate it to push the cauldron away from the setup. The comparator will stay on.
3. It is possible to turn the comparator off by updating any adjacent space to the comparator, or placing another block that can output a redstone signal in the original position of the filled cauldron.