Last boss after you damage the seal, the next round of adds spawn, and they are many. We’re talking about maybe 10 – 15 veterans together with simple ones and this is at lvl10. My question is if this is a bug or do we just need to get better at playing the game? 
Cliffside Fractal - is it a bug or not?
Can’t remember having this many spawns on lvl10 today, but we did at level 20, we just liked the challenge and found a way to deal with it.
Also de AoE Blast skill of this boss has a seemingly unnatural low cooldown.
If you pull the boss in to the side room you do not have to deal with the adds the whole time. For the most part the adds do not all follow you in there. The down side to this is you have a much smaller area to deal with his AOE. When he goes invulnerable and you need to smash the seal, you do your best to take down one and get out of there. It sounds easier than it is…and it is slow… but doable
Yeah we did that today, it worked but it feels like you shouldn’t do that in that way.