Edit - Another one of my target dummies was also able to kill 5 level 9 mobs SOLO. WTF? these same mobs are usually able to kill me with 3 of them on me. :L However, he took them on individually not at the same time :P
2 Years since I reported this bug, it's minor but I decided to check on it anyway with new builds etc.
Positive : The target dummy isn't op
Negative : That's because the target dummy doesn't taunt or attract mobs. It still follows you around, and instead of lasting for the "15 seconds" it says it will, the dummy actually lasts until you log out, or attempt to summon another. (Or killed by an enemy faction member)