mismatching

/M IH0 S M AE1 CH IH0 NG/
verb
  1. 1

    To match unsuitably; to fail to match

noun
  1. 1

    An incorrect match or pairing; a mismatch.

Source: https://en.wiktionary.org/wiki/mismatch, https://en.wiktionary.org/wiki/mismatching