Yea, people can't just mysteriously become OP. Either you have a malicious plugin/mod or a bad configuration. Properly configured, nobody can be op'd until you do it for them.
Also ROFL.. did you seriously censor your UUID? That's public information you know heh. e.g. your UUID is 0458b9e9-0d9e-4c35-b2f2-8a421cb3b0df and Donut's is c290fb0d-8a9f-4e18-b08b-e53fa10faf7d