My tank has CampfireOn=1 and always starts on a flat-enough surface. I was able to manually move them back when I wandered by by hitting my fellowship hotbutton.
I'm curious if it has something to do with the evac moving them out of the CampRadiusExceed range and staying in the same zone. Even if my tank made it back solo he would get caught in a loop of "let me pull this mob I can't handle alone," dying, and losing XP.