Affects Version/s: 1.15.2 Pre-Release 1, 1.15.2 Pre-release 2, 1.15.2
Fix Version/s: 20w06a
Items with transparent models, such as stained glass variants, render differently when a glowing entity is visible in frame. This also happens on items rendered on entities, such as armor stands and item frames.
1. Drop white stained glass and see that you can see the inside of the item model.
2. Summon a glowing entity
3. Notice that the item model may now renders flat, and the inside is no longer visible
4. When you go near the item and it is picked up, for a brief moment, it may appear to render correctly again.
According to Bartosz Bok, this issue is somewhat unpredictable as a result of state leak, which depends on order of entity rendering.