This happens to me on regular basis, and is caused by Control Pad / Hot bar layout. While in Cleric Stance and doing DPS, I usually open with Aero II, then Aero,
Aero II and Cleric Stance are both on Hotbar 2.
Aero is on Hotbar 1 while the Bomb Dance in the same spot on Hotbar 2.

The number of times my hotbar switch goofs and I start dancing the middle of battle can be comical. I really should just update my Hotbar 2 and move the dance to hotbar 3 or 4.