Thrown potions don't have shadows in deferred rendering

Steps to Reproduce:

1. Import any resource pack with PBR capabilities;
2. Enable the experimental toggle for Render Dragon features;
3. Switch rendering mode to "Deferred Technical Preview";
4. Throw a splash potion, lingering potion or bottle o' enchanting.

Observed Results:
These items don't cast shadows on the ground.

Expected Results:
These items cast shadows on the ground, just like all the other thrown items.

Screenshots/Videos attached: Yes

Notes: Even XP orbs cast shadows!