Different boss strategies on different data centers

[Grembo]

Yeah Chaos has always done it in the middle.

I've seen the OP's situation many times in many different instances and always put it down to an over reliance on video guides.

It feels like 99% of the player base over on the EU and NA servers don't actually learn the fights or pay attention to the mechanics, they just do Mr Happy's dance routine and expect the other 7 people in their party to be doing the same

...if these kind of players even catch a glimpse of an alternative strat, their poor brains just explode.