The heat is probably from binding brakes either from a sticky caliper or pads.
Maybe debris picked up and the disc rubbing it?
I had similar on a car a few years ago. A clean up failed as an easy first fix. It was a seizing caliper in the end.
Symptoms were exactly as you described.
I tried repeated brake/ pushing pistons back but to no avail.
Replaced the caliper in the end...
The problem was a damaged rubber seal allowed water to get onto the piston causing slight corrosion.
