I have this same bug, and it's really wonky. It seems to trigger when I fast travel to specific places, like Abernathy Farm. If I go from Abernathy Farm to Starlight Drive-In, the bug persists (Sanctuary shows incorrect numbers), but if I go back to Sanctuary, then to Starlight Drive-In, and *then* to Abernathy Farm, everything's great. I haven't tested other locations, yet. Bizarre.