I wouldn't exactly call the first part a bug, more like an unintended consequence. After raiding Starlight to turn it into a vassal settlement (it was prebuilt), it wouldn't complete, and it took me longer than I'd care to admit to look at the quest objective and figure out that it was leading me to Back Street Apparel. It seems like it counts the kidnapped settler for the quest to obtain Starlight as a settler that needs to be downed. I had previously been to Starlight and talked to the settler that asked me to save their friend, but exited the dialogue, knowing that I wanted to take it as a vassal, so I didn't have it as an active quest. I also did some testing on it. After going to Back Street Apparel, trying it before and after starting the raid so I knew it wouldn't effect anything, it turns out that the "settler" that was kidnapped was a molerat. It wasn't interactable (as expected) but it didn't aggro to me. Also, killing it failed the quest to obtain Starlight normally. However, once the raid has been started, the molerat cannot be killed or downed, and cannot be disabled through console.