I was eating a golden apple to regen health on a UHC server. The absorption potion effect image works fine until you pick up an item from the 1st, 4th, 6th, 8th, or 9th slots on your hotbar from your inventory, at which point it has a black frame and 4 white squares surround it.
1. Go in survival (or possibly creative, not tested)
2. Eat a golden apple
3. Open your inventory
4. Pick up an item from the 1st, 4th, 6th, 8th, or 9th slot of your hotbar.
5. Look at the absorption effect image.