Where in the phase are you? I.e. is it before or after Kephess pulls everyone in at 58% health?
There are two additional things to look for in this fight that you didn't mention:
1) Above 58%: Kephess will put a very nasty DOT on whoever has aggro after doing his red-circle jumps. It is strongly preferred to do a tank swap when that happens. The debuff icon is orange-ish and looks like a guy holding a lightsaber.
2) Below 58%: Taunting during breath of the masters might be too late. We've noticed that it works a lot better to taunt him immediately after the knockback instead (which should happen just before he casts breath of the masters). Any damage taken after breath of the masters will one-shot the tank having the debuff.
You got me thinking - how long does this dot last? if you happen to know? I'm aware of its existence, just not of its duration.