Well let's do a flash back to the 40m range cap, commonly known as the "range nurf". Funcom's reasoning was, mobs could be attacked outside of their current GS, and could not find their way into your GS. They didn't have the resources to fix the AI so they could make it into the correct GS. They had 2 solutions, either hard cap range or make mobs teleport to you if you moved out of their range. They opted for the Hard Range Cap stating that teleporting mobs was a cheep and unrealistic solution.
Well teleporting boss mobs is essentially the same thing. Instead of them coming to us, we are brought to them. If you move out of their agg range and your pet is holding agg, they can't teleport you anyway when they finish off your pet, but the part of this that is so ANNOYING, is that they teleport you when you are 2 feet to them and you are not running away, where your droid and 2 charmed pets are fighting them, and that breaks the 2 charmed pets charm then the boss and the 2 ex-charms are all attacking you at once.
If you are going to keep this boss warping please make it not break charms, and not STOP attacks. It's so buggy and yet it was put on live ages ago and has not been improved, unless, of course, all these effects are intended.