Mostly happens when:

• Player runs away from mob without attacking the mob
• Mob friendly-fires enchanted mob before taking any damage from player
• Mob 'ninjas' into blocks and dies there
• Mob despawns while targeting a player (minecraft...)
• Mob is killed by another player, while targeting local player (bug appears very rarely in this situation)

Finding another mob with Choke and killing it fixes the issue, but only if mob was killed not by conditions above

Going to test

Fix seems to work.

Also, #160 - Your closest license is MIT (i use Apache 2.0 for my gmod addons).

The problem is that a modifiers target may change or it may not receive update ticks to "reset" a player entitiy from a modded state. I have implemented a timer that keeps track of modified players and calls a reset for each modifier when they stopped messing with him:

85ae6ae

I won't be able to test this myself. See if this helps, if you can. Also, the fix is only for 1.12.2

And thank you, for reporting it