I went with Jammer (and Ada) to investigate the location of the scouts being cut to pieces by caps. About near where the raiders are hanging shit on the tree both Jammer and Ada refused to continue towards the quest marker. Having seen this oddity in the past using mods that add new land north of Sanctuary, it seems an awful lot like no navmesh or navmesh mismatch. Does anyone have any thoughts about it? My resolution: I used prid and then moveto player to drag Jammer to the location, but then had to sleep to get him to engage with the next section of the quest, but I did move past it. I also had to prid/move to to get him out of there.