Three times now when I've gone to defend Starlight Drive-In the settlers have all been happy saying that we kicked raider butt and that they really showed them what for. There's 7 settlers there and their happiness is 67^. If I leave and do some general exploring, after a while I'll notice that on the map the Starlight Drive-In has 2 settlers and it's happiness is 0. So I travel back and there's now 7 settlers again but all defences, generators and water treatment devices are broken. Happiness will be 65v.

When I go to fix the defences and generators they list all the materials I need to fix the items but their values are all zero (0) and they definitely don't use any junk to repair. I have 5 Large generators, 3 spotlights, 3 guard defence barriers, and about 8 large lazer turrets.

This only happens to Starlight Drive-In, Sanctuary Hills and the Castle don't have this issue.