If the player has health at a half-integer value (for example through the use of the /attribute command), the odd health number will result in a half-full heart appearing at the top of the health bar. This half heart is misleading as the empty contents appear to imply that the player can heal this, despite this not being the case. Hearts which would be fully empty are however deducted from the total count of hearts, so this half one being there doesn't make much sense.

As seen in the provided screenshots, the player's health is at 1 and the max health is also set at 1. Note how drinking a health potion does absolutely nothing, whereas the health bar would visually imply that there is still health to be gained by drinking it.

Fixing this would involve having exclusive "non half-empty half-heart" sprites introduced for this case.