Blaze's don't drop blaze rods when killed by Powder Snow

How to reproduce:
1. Place 2 powder snow blocks; one on top of the other.
2. Surround those blocks with other solid blocks.
3. Grab a blaze spawn egg and spawn a bunch in the powder snow and wait for them to die.
4. Remove the powder snow and there will be no blaze rods from the blaze.

Observed Results:
No drops come from blaze when killed by powder snow.

Expected Results:
Blaze rods should be dropped when a blaze is killed by powder snow.