In Grim Batol on first boss, my MI aggroed the mobs on the other side of that rift (next to the bridge, the pack you normally skip). We had aggroed them before once during trash pulls, though.
One thing I have noticed: Odd things only happen when you pop MI before doing any damage on the boss. If you launch a quick IL or FrB and pop MI afterwards, everything is perfectly fine.
I tried four times on Heroic stonecore, each time a different time casting MI and watching what happens, note, this only happens sparadically and once it does I cant get it to stop until we move to next boss so i just bypass my MI for this fight. I tried casting MI right away, after aggro, probabaly before attacking, I tried casting one dps spell and then MI, i tried dpsing 15 seconds before MI, and i tried popping all CD and mages "lust", each and everytime the same mobs pulled.
It sucks wondering before you pop MI if this is going to be the time I cause a wipe, any ideas what is causing this to happen?