After finishing Gorsky's questline in Core City, I aggroed the Muties right outside the base and ran back towards Gorsky. Gorsky and Sneaky came to help, but they don't see the Muties. So they just run back and forth while I combat the Muties alone.
Steps to reproduce:
1) Finish Gorsky's questline in Core City.
2) Leave base towards the south, sneak by the Muties.
3) Come back later (after Dirty Tom has set up shop). Right outside there are muties to the south. I aggro them and run back towards Gorsky, to get some help.
4) Gorsky and Sneaky come running to help, but they don't see the Muties and the Muties don't see them. So I fight it out alone with the Muties, while Gorsky and Sneaky just run back and forth while the combat is going on right next to them. Their barks show that they are looking for enemies but don't see any.