General Information
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• I play...
  • [ x ] With a large modpack
  • Only with CQR and it's dependencies
• The issue occurs in...
  • [ x ] Singleplayer
  • Multiplayer
• [ 1 ] I have searched for this or a similar issue before reporting and it was either (1) not previously reported, or (2) previously fixed and I'm having the same problem.
• [ x ] I am using the latest version of the mod (all versions can be found on github under releases)
• [ x ] I read through the FAQ and I could not find something helpful (FAQ)
• I reproduced the bug without any other mod's except forge, cqr and it's dependencies
• [ x ] The game crashes because of this bug

Describe the bug
A clear and concise description of what the bug is.
abyss walker king and illusioners from engender mod fought each other and this crash happened
To Reproduce
Steps to reproduce the behavior:

1. Go to ...
2. Use item ... abyss walker king spawn egg, illusioner fusion(engender mod)
3. Place block ...
4. ...

Screenshots
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Versions (Note that 'latest' is NOT a valid version!
Chocolate Quest Repoured: 2.6.7B
Forge: 14.23.5.2860
Minecraft: 1.12.2
Other mods (necessary to reproduce the bug): engender mod

Log File
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https://gist.github.com/rebarakuk/a1cd2032a1cfa28e5c4ce3eecac06579

Not reproducable, the crash hints at a concurrent modification exception occuring somewhere in the update method of entities, hwoever, that happens in MC classes, not cqr classes and we do not modify these. Report it to engender, we can't reproduce it, the last call in CQR code is a call to minecraft base classes

This might be a tick error, because when I installed tickrate changer which synchronizes server and client ticks, this crash doesn't happen

Again: This doesn't happen with just CQR, report it to engender, we won't work on this and it is not reproducible for us, the crash report is also pretty useless cause the exception can't raise from where it last was in our classes.