Hi since a day or two ive been getting this strange bug after the ball event triggers. It makes me only agro one or two mobs after the event is over, i then need to reboot the entire game to fix it untill the next ball event and repeat.

I'm experiencing the same exact issue, back to Zephyros til this is fixed

Aggro is definitely bugged. Just tried two servers and could only pull 4–6 mobs at a time right from the start, so the orb event didn't even matter.

Might help to give a class that you're on when it happens. I've not had the issue with awak dosa or awak witch.

Same problem here on Succ Guardian. Starts off fine with 10 mob pulls but eventually it wittles down to ~5 mobs or so. Hitting more mobs does nothing, they don't move, and their HP just keeps resetting.  

Edit: Got 7K trash with Lv2 loot scroll (no agris) in 1hr. :/

Thought it was my imagination the first time but I've been encountering the same/similar issue with succession Maegu at the central Marni rotation. Today it was severe enough that I dropped down to 3 or so maximum enemies aggro'd. Lost a fair bit of efficiency and potential orbs by having to swap channels so often to try and reset.

It may have been a fluke but my sessions utilizing the Marni Realm function seemed to avoid the degradation.

Had the same issue with Seraph at main and statue rotations. It usually starts after the Sycraia's Memory event. It sometimes resolves itself after 15 or 20 minutes, but most times doesn't resolve itself. It usually caps me to aggroing 5 or 6 mobs. Also, the mobs that pull are never the ones closeby - they pull from far away. I went to Marni Realm and didn't have the issue once, however.