Having one major moon that is large enough to move the barycenter outside the planet crops up pretty regularly among dwarf planets in the outer solar system:
en.wikipedia.org/wiki/Charon_...
en.wikipedia.org/wiki/Dysnomi...
en.wikipedia.org/wiki/Vanth_(...
en.wikipedia.org/wiki/...
en.wikipedia.org/wiki/Charon_...
en.wikipedia.org/wiki/Dysnomi...
en.wikipedia.org/wiki/Vanth_(...
en.wikipedia.org/wiki/...
