2012 Acura TL intermittent grinding noise while braking

Images here: https://imgur.com/a/R0wC1m8

Our 2012 Acura TL (FWD) has been making a grinding noise when braking, but very infrequently. We can be driving for 30 minutes and no noise, and then it will randomly do it. Or right after starting up, it will do it at the first stop sign, and then not again the rest of the drive.

Seems to be coming from the front driver side, and I noticed this lip on the rotor. Other three don't seem to have it. Could this be the cause?

If it is the cause however, shouldn't it be making a noise at all times when braking?

It almost sounds like a fender well cover/splash shield rubbing the tire, but I didn't find anything that would obviously point to that. What else could I look for?

Thanks!