It's entirely reasonable to move out of the AoE markers, even if you trust the healer, you don't want to take unnecessary damage as that means you'll need less healing, but try to move back to where you were before asap, that's usually what DPS will anticipate.
You can move as soon as the marker disappears, so reposition and you will usually be back in the front by the time the boss has finished using it's attack, and so it shouldn't, in most cases, turn at all.