[vault (v.1) :] [...] from Vulgar Latin *volvitare "to turn, leap,"
frequentative of Latin volvere "to turn, turn around, roll" (see volvox). [...]
I ask not about the meanings "turn" or "turn around" which both verbs share, but only about the meaning of "leap" that appears new to Vulgar Latin and (superficially) unconnected to the notion of to "turn, roll."