Unable to gain Combat XP through Mobs.

For some reason, when killing a mob, I gain no combat xp. Some mobs straight up say +0 combat xp, while others actually say +4k combat xp but adds literally nothing to my actual xp meter. I'm only able to get xp through quests, mini quests, and caves, but can't grind mobs to get any xp, so I'm kinda stuck in terms of leveling. This has happened across multiple profiles on two different accounts, so I'm kinda just stuck there, but it only affects me if my character is above level 100. I've tried /guild xp 0 and on the other account I'm not even in a guild. Is anyone else having this issue?