Mob Despawn Seemingly Randomly [1.19.3] [java.util.ConcurrentModificationException: null]
Summary
I have a custom mob that are Ravagers, these Ravagers have 2 primary features; they do not attack players, and players can mount them. Seemingly randomly, these mobs appear to all encounter a null error at the same time and de-spawn. I am on Paper 1.19.3-379 and mythic mobs 5.2.1-fd1d0777
Steps to reproduce
https://pastebin.com/kcEDUcnU - install this mob
- Spawn this mob
- use nametag on mobs
- Wait from 24 hrs to 1 week
- Mobs will throw error and despawn. This can happen when no players are in the area, or when a player is looking directly at the mobs.
Current behavior
- Mobs despawn randomly after an error
Intended correct behavior
- Mobs should not despawn
Server log file
Debug log snippet
https://pastebin.com/8ysYZyEy [4 ravagers in question, 4 errors thrown up, all despawned at the same time, no players were interacting with the ravagers when this happened].
Proposed fixes
This appears to have only started happening post 1.19.3's update, either because of something paper did, or something that mythic mobs changed, unclear what.