Yeah, this was exactly my problem. No aoe circle for fireball. All the other aoe markers showed up just fine for me, and I assume the other three in my group were seeing the fireball markers, since they were okay, but I got absolutely no warning whatsoever. Interestingly, the dark dragons on 91-100 did give me the warning markers so I was okay with them. HOPEFULLY it was a one-time glitch in my u.i. I'll be taking my 2nd run on 81-90 here shortly so we'll see. Either way I'll report in here and turn in a glitch report if it's still happening.