Apologies for the tardy follow-up.
The problem was fixed by changing the front brake pads.
Although the pads were at 50% wear, it seemed to be the easiest and most cost effective attempt on my part to eliminate possible causes.
I believe factory authorized service did try their best to diagnose the cause of the pulling (after numerous times of not being able to verify complaint). However, we came to a point where service would not just "start replacing parts without diagnosing it as the cause of the problem".
FYI- attempts to cure pulling prior to changing pads included: 1) exchanging brake pads- left to right, 2) hand sanding front rotors, 3) inspecting all calipers of proper functioning, 4) front end alignment, 5) tire balancing and rim inspection for bending/ damage, & 6)brake system bleeding