Rent out Laguna Seca (inviting me at no charge off course
) and run it backwards for a day/weekend with fresh pads and see if other side's outer front wears as quickly...
Could you imagine running UP the Corkscrew???
Just kidding...
Inner pads typically wear faster than outers. Since (by your comments) other 3 front pads are ~ 50% life (and rears not needing replacement either) you likely have a problem w/ that caliper dragging/stuck. There's ~ 25% meat left when sensor is triggered meaning that pad is wearing 50% faster than others. If both pads in same caliper were even you could pull in ABS and/or t/c as possibility but since only one... caliper is very suspect. How was wear across worn pad itself - even?
You can try pulling and inspect pistons etc. but likely a rebuild will be your solution and might as well do both fronts at same time.
Good luck
