The resistance thermal coefficient of most¹ materials is positive, which is why parallelizing connectors works; contact points that heat up due to poor contact

The resistance thermal coefficient of most¹ materials is positive, which is why parallelizing connectors works; contact points that heat up due to poor contact increase in resistance and therefore current shifts to other connections that have less resistance. This is a plain case of having not enough contact area (or not having enough mechanical safety/UX to ensure full insertion.) ¹ most: pretty much everything that isn't explicitly researched/chosen for its negative coefficient. Definitely all conductor and connector materials. But some semiconductors are known footguns for not supporting parallelization due to negative coefficients and runaway heat effects (one of the things you learn in EE education). P.S.: materials with negative thermal coefficient don't turn into superconductors if you heat them far enough; the coefficient is not constant across temperature and it's either just not linear and approaches some nonzero value, or it just flips to a positive coefficient at some higher temperature. Or the material just melts or burns and then behaves differently anyway.