Grass blocks underneath waterlogged blocks do not turn into dirt

Summary:
All waterlogged blocks except for hoppers and mob spawners prevent grass blocks from turning into dirt.

The full list of waterloggable blocks can be found on the Minecraft Wiki.

Steps to Reproduce:

1. Place a grass block underwater
2. Place a waterloggable block on top of it
3. Set the random tick speed to a high number

Observed Results:
The grass block does not turn into dirt.

Expected Results:
The grass block should turn into dirt.