CAs use a different ShadowStyle (SpellAttack...something, didn't write it down).
OnShow code on the bubble to trigger only upon the AA ShadowStyle could be like this:
Parent.Parent.AutoAttackTimer.Trigger.Activated=(LowerText.ShadowStyle=='/ShadowStyles.Outline.BlackOutline1')
Only you couldn't trigger the timer directly but would trigger a second comparison that checks the color here, and only then triggers the timer.