Repro Steps:
1. Create a new World in Creative mode.
2. Build Nether Portal and enter it.
3. Spawn Piglins and Hoglin using Spawn Egg.
4. Wait until Piglins kill Hoglins.
5. Observe the issue.

Observed result:
Piglins don't trigger celebration state after killing Hoglins. Only thing that appears is Hunt Cooldown. This issue also occurs with natural spawned Piglins and Hoglins.

Expected result:
Piglins have Celebration State after killing Hoglins.