I am not a professional. This is just my opinion. I could be wrong.
Well the first obvious thing I see is that you did not mention anything about the condition of your rotors. If you did not machine your rotors then your pads are going to wear uneven from the beggining. Here is a list of possible causes.
#1. not machining your rotors after a pad slap.
#2. Warped rotors.
#3. to much wheel bearing endplay.
#4. Frozen brake caliper.
#5. Clogged brake line or a leaky caliper piston.
These are multiple reasons. But again since you did not mention anything about mating your rotors to the new pads. I would go with that first. Check the condition of your rotors. Don't just look at them. Do some measurements and compare them to spec.