In situations where an angered Enderman normally should stop being hostile towards the player, the Enderman instead continues being hostile, as long as the player is visible. The only way to turn them permanently neutral again is if the player dies.

The Enderman can turn temporarily neutral if the player is not in their line of sight when:

1. The Enderman loses interest and teleports away due to daytime, or
2. The player changes to creative mode

Normally, this should be "permanent". But due to the bug, as soon as the player is back in survival mode and in their line of sight, they automatically turn hostile without provoking them.

To reproduce

1. Summon or find an Enderman.
2. Set time to day, and gamemode to survival.
3. Provoke the Enderman by looking at it or attacking it
4. Enter a building where the Enderman doesn't have a line of sight to you (use glass blocks to see them becoming neutral again).
5. Wait.
6. Enderman loses interest, and is no longer hostile. (The stare sound also plays again - MC-216648).
7. Leave the building.
   → The Enderman instantly sees you and is suddenly aggressive again without being provoked.

The issue in the code might be that the Enderman never forgets about the player even after becoming neutral, and only forgets if the player dies.

Possibly related to/caused by MC-197635 becoming fixed, which seems to be related to the fix of MC-188506 in the same snapshot.