Rotors heating up and catching fire, Toyota Camry V6 LE Sport Coup (ABS)?

[Savvy]

Last year I was driving down the express way and I suddenly smelled something burning and immediately I pulled to the side. I got out of the car and found that the rear driver side rotor was on fire along the caliper. Later on the mechanic diagnosed that the caliper had become too tight on the rotor that's why the rotor was heating up. At the same time when he was checking the other wheels he found the the front passenger side wheel was somewhat stiff and and there was some carbon dust on the rim. For the front wheel he just changed the hose and for the rear wheel he changed the caliper and everything was fine after that. About a couple months ago I felt the front passenger side rotor was burning to touch. This time the mechanic said its because of the caliper was clenching tightly around the rotor. Every other wheel was fine and didn't feel hot to touch then. I changed the front the passenger side brake caliper and the wheel was now spinning freely. A couple of days later I smelled the front driver side rotor burning. I'm now at my wit's end trying to figure out the problem. Three out of the four wheels have had the same problem. I clearly remember this wheel was spinning freely and wasn't heating up even a bit when the other wheel was being fixed. I wonder if the mechanic did something wrong to this wheel when he was bleeding the system. What's really causing the same problem again and again to all the wheels one after another? Is there any bigger issue that causes to the caliper and the hose to jam and cause the rotors burn, if so then why aren't all the wheels being affected at the same time? Please help me out