Industrial Foregoing Version: 1.12.2-1.8.1-119
TeslaCoreLib Version: 1.12-1.0.12
Crashlog (If Any): n/a

Your check to see if a player is not a contributor instead gives everyone not on the list cat ears:

if (Arrays.asList(contributors.uuid).contains(entitylivingbaseIn.getUniqueID().toString())) return;

At least, that's my theory. I only noticed just recently since I'm in SSP.