Can Draven Vanquisher's defend trigger activate multiple times in a single combat if the attacking unit is removed and then returns?

Ruling: Draven's defend trigger can only be fulfilled once per combat. It will trigger the first time he gains the defender designation in a given combat, even if the attacking unit is removed and returns during the same showdown.

Nuances:

• Removing the attacking unit (e.g., with Force of Fire) and having it return (e.g., with Ride the Wind) during the same combat does not allow Draven's trigger to activate again