I play with a buddy through steam and on PC.
After killing 4 rivals in a small area in the lower Marshlands my team mate was unable to loot them and also the plundra and other base facilities were unusable which were just prior usable because we were at the home base and he had no issue. I checked my settings and everything was set for him to be able to do anything he needed. This isn’t the first time he has been unable to loot downed robots but this is the worst since 4 of them were rivals we had downed. One of them was an Apoc Tank, which I let him kill solo so he could finish the Wild West achievement. He got the credit and the achievement but was then unable to loot the machine. Him relogging and rejoining my game gave him access to facilities but lost access to the downed machines.
This may be relevant, he was switching to binoculars while fighting the Apoc Tank Rival to both mark and check it’s remaining HP. It was after that fight he was unable to loot any machines.