Arena (gladiator)- purple critters?

Just wondering if anyone can help. Sometimes in Gladiator matches (playing 1v1 with any number of glads) me or my opponent will spawn mobs equal to our own selection, but with purple name tags (and hostile and not controllable). Anyone know what this is about? Sometimes happens a lot and the person spawning them can be half dead before the real battle even starts.

Its happened to me a few times, I think it must be a bug, seems like it trys to spawn the gladiators again, realises it has already so doesn't give a double set and instead just provides an instant battle which the other gladiator master can then mop up.

CAn't rememebr if I have /bug ed it yet and im not sure if it is in the technical issues/bugs section, maybe Bridger could move this topic there?