Garuda - Dread Mirror doesn't follow use ability on selection toggled off

[Ordel]

When Use Ability on Selection is toggled off, Dread Mirror still casts when I tap my 1 key (but don't tap a cast currently selected ability button). When I load into missions, it doesn't start off like that initially; I can select Dread Mirror without casting it. But later in the mission, tapping just the 1 key casts it.