Sudden onsets of high-voltage differential charging on spacecraft in an ambient environment may affect operations and the survival of on-board electronics. Triple-root jumps may be very sudden. We discuss two aspects, one theoretical and one observational. By using current balance, the theoretical parametric domain in which triple-root jumps may occur for a surface material in a double Maxwellian electron environment has been calculated. The relation between the domain and the ''critical'' or ''threshold'' temperature for a material is revealed. We present an example of the prediction of the occurrence for a triple-root spacecraft potential jump in a time-varying space environment.