Random server crashes from skills

Summary

Thread dump, I believe caused by the skill below. Skill: https://pastebin.com/W0wyw7Wc Thread dump: https://pastebin.com/arZv0gGK

Steps to reproduce

No idea I only have suspisions of what is causing it.

Current behavior

Server crashes with the above thread dump

Intended correct behavior

For it to not crash >.>

Server log file

https://pastebin.com/iuV2AHZH

Debug log snippet

I can't have the debug on 24/7 as it spams console and the crashes are random.