Uneven brake pad wear

[oragex]

As above, check the slide pins at the wheel with unworn pads, upon breaking the pins loose, try removing them by hand, see how easy they turn. Also look where the pad 'legs' sit against the caliper bracket - see if there's a deep groove in there that may prevent the pad from sliding properly (less probably the issue). I'd rather clean and keep the boots over the pins without grease than use a random silicone grease that starts sticking withing a few months.

The ABS valve unit is the silver piece that sits on top of the ABS controller/module. There are solenoids inside it, which may get stuck when new pads are forced in place without first releasing the bleeder (just my theory)

[MDK]

The auto parts store will help you with the right grease...

[virtualking]

Its an issue of brake fluid according to me, you should change it frequently so that it works smooth

[WhatAmIDoing]

They sell high temp brake grease at any auto parts store. You only need a little bit for each brake, so no need to buy a huge tube or tub. Grease the pins, slides, where the brake pad sits, and the backs of the pads (do not get this stuff on the friction surface or rotor). There's lots of videos on YouTube showing you how to grease brakes properly. You may want to use a wire brush first and remove some rust on the caliper.

Since the wear is only on one pad, my logic concludes that the pads are not recentering after braking, likely due to excess friction on the slides or pins preventing them from doing so. If your caliper is truly seized, both pads should be worn out (mine were when this happened).

Since you are getting the brake fluid flushed, replacing the front rubber brake hoses may be recommended just as preventative maintenance. A set is cheap on FCP Euro, and this job is easier when the master cylinder isn't full.