If they are doing this while you are standing there, take a pineknot, tell them to get out, then give them a migraine. If they are going back to a tied hog, leave someone there with a good green limb and knock all the dust off them and make them get ahead.
They both do it while the catch dog has the hog. Once I get there and establish that it is my hog, one will role out and hunt. The other sometimes rolls out and sometimes hangs out. Neither will go back to a dead or tied hog.