Hibeter

Okay so I have a 1.12.2 server me and a few friends play on. We were playing today and one of my buddies was boating and suddenly the server crashed. we originally thought it was me and my other friend because we were exploring but then found out it was something he was loading in the boat. Heres the server crash report: https://pastebin.com/y99eVqzC Any Idea on what could be causing this? I already looked up the error and it didn't really relate to anything in this situation.