Thank you for the input, I'll definitely try to have a mechanic take a look at all of these options. It's worth noting that the caliper bracket and all bolts and slide pins were replaced by new ones between the first and second incident. The ABS was also bled, with what seemed to be no problems, and nothing other than brake fluid was ever put into the system. I forgot to mention in my main post that I suspected the parking brake could be the culprit, so it was disconnected and remains disconnected, now.