Steps to reproduce

1. Set up an area with a grass block floor where some of the grass blocks have light level of 3 or lower in the space above them. This can be in an overworld structure with a solid roof, or a cave (since skylight at midnight is light level 4), or in the nether or end where there is no lighting nearby.
2. Place chests on top of the grass blocks.

Expected result

The grass does not change.

Actual result

Grass blocks change to dirt where the light level in the space above them is 3 or lower.

This only happens in the Nether and not the Overworld. Grass turns to dirt despite the presence of any light sources. This also happens with hoppers and works in both dimensions (this part of bug is a duplicate of MCPE-62132.