@greg so by heating up the MLCCs, you end up bringing the lattice up to the Curie temperature, which reforms the tetragonal lattice, recreating all the spontaneously polarised electric domains.
and that's why sticking a towel around your xbox works. it's also why the "reflow the BGA" trick also seems to work. nothing to do with BGA balls, it's just the hot air gun resetting the MLCC aging.
(note: temperature is weird at the atomic scale; you don't actually need the ambient to get up to 120°C)