I think it's pathing, rather than stat based. I've also had Karlach, too, (and my Monk main) get stuck more often than Gale.
But I've also found an easy fix. Hit the Ungroup/Group key (G) twice. This shakes them up and they retry their path. Usually, they'll jump correctly to catch up after doing this once.
Still, if you have your group partially ungrouped, then it's pretty annoying. If you've made a second jump beofre, they also probably won't figure out how to path to you either.