Ok so I figured out what the problem is – I had another building right by the entrance to it, so nobody could path to the Gatherer Shelter or whatever. That would make this NOT A BUG – but by way of suggestion, perhaps it should have the directional ‘don’t put anything here’ arrows like most of the other buildings including the houses etc. or other small structures like the Smoking Shed do?
I notice the Woodcutters Cabin at least doesn’t have them either. People should definitely not be stupid like me and block off the entrance, but I do think it would be a beneficial enhancement to these structures.