The bug

The hopper model has a two pixel thick rim at the top, like cauldrons and composters. However, the top texture applied to the top face is three pixels thick, unlike cauldrons and composters.

This inner ring of pixels is unused in Java Edition; see MC-262454.

How to reproduce

1. Place a hopper
2. Place a cauldron
3. Compare the top textures
4. Compare the inner wall thicknesses

Expected results

The hopper's top rim texture would be two pixels thick, just like the rim of the cauldron is.

Actual results

It is three pixels wide instead.

How to fix

The fix for this should be the same as the fix for MC-262454 - just change the hopper top texture to get rid of the innermost ring of pixels.