there aren't any return springs so any release movement is caused by square cut O rings. There is no way a rotor can run so true as to not kick the outer pad away from the rotor a few thousandths, unless the caliper cannot move in the ways or on the pins depending on what design it is. Pin mounted calipers do relieve the outer pad better than calipers in machined ways due to again square cut rubber at the pins.
The factory service manuals show rubber bands used at way mounted calipers but we rarely see those in use.
I really doubt any of this is relative to sticking to overheating brakes but.. when the caliper does release force on the outer pad that pad should go with the caliper and not lay loose against the rotor.