Everytime someone does /wondertrade(or /wt) <enter slot 1-6 here> confirm
It says this error, and they DO have permission to use wondertrade, luckly their pokemon stays in the roster, its just the error showing up and nothing else in console.
Error occurred while executing command: com.pixelmonmod.pixelmon.api.events.pixelmondeletedevent.(Lnet/minecraft/entity/player/entityplayerMP;Lnet/minecraft/nbt/NBTTagCompound;)V