Magic The Gathering, Blinking the source of a transformation
If you blink Archangel Avacyn while its transform trigger is on the stack, the new Archangel object will not transform.

You are correct in that the transform trigger will still resolve, even though its source object no longer exists. However, the Archangel that put the transform trigger on the stack was also the object to be flipped. When you blinked the original Archangel, the transform trigger lost track of that object. The transform ability will resolve, but it will not do anything.


  400.7. An object that moves from one zone to another becomes a new object with no memory of, or relation to, its previous existence.