When grass or mycelium grows under powder snow the grass is not snowy

When powdered snow is placed on a grass block, the grass block turns into a snowy version. However, When it spreads, this is not the case. Note: Also happens with Mycelium.

Steps to Reproduce

1. Place powdered snow on top of dirt near grass blocks
2. Increase the tick speed to 1000
   The grass grows to under the powdered snow but isn't snowy.