Don't know if this is anything to do with problems mentioned, but in the past we had a problem with a car brakes, the discs had warped slightly. The explanation was put forward that due to violent braking from speed or running downhill whilst relying on the brakes only. On stopping then the driver leaving his foot on the brake pedal caused the problem. In effect it fried the linings and discs.Not letting them have air circulation.
It cost us, the company, a new set of pads and discs to sort the problem.
We were told it is an easy thing to do .