Server crashes when running a fish event

[MasterGabeMOD]

Here's the error log: https://pastebin.com/BBLrTdVg

Config.yml: https://pastebin.com/yLxT1eHL

Fish.yml: https://pastebin.com/Sgu4L5mn

Baits.yml: https://pastebin.com/vvLnJg9g

Competitions.yml: https://pastebin.com/FWtVWbg6

The rest of the configs are defaults.

We were initially running version 1.6.11.16 from Spigot, but I compiled the latest 1.6.11.17 from here on Github to see if that would resolve it. Unfortunately, the same crash error persists. We're running Purpur 1.20.2.

Edit: Just to note on this, the crash occurs after the event ends.