UUID from Entity and Entity Iterator is different??

So basically I have this very advanced xp system and basically when an entity is attacked it stores the UUID of attacker and the damage dealt by storing multiple nbt tags. When the entity dies xp gets divided to the entities that did damage to it but I came across a problem when doing so. Basically when the entity dies I made it so it checks the UUID of every mob in the radius(thro the "for each entity as 'entity iterator' in square cube with size" block) and checks if the entity iterator's uuid matches the stored attacker's uuid. When running some experiments(killing mobs) it looks the UUID nbt tag stored does not match the entity iterator UUID(which is supposed to be my UUID as a user). Does anybody know why this is happening?? And how to fix? I can give more info and images if anybody can help.

P.S. I'm using a uuid plugin, here's the link: https://mcreator.net/plugin/72173/uuid-procedures