For whatever reason, I cannot interact with the door to the Drug Den near the USS Constitution. My character clips through the door & said door cannot be interacted with period. Makes no sense whatsoever other than yet another oversight by Bethesda's inept & unqualified QA team.

Works fine for me. Have you tried reloading a save from before you approached or fast traveling away and back?

That happens randomly on any door, Saugus Ironworks for me just now. Maybe it's still in LOD mode, and not the one it should at close range? I don't know. But for me at least it's a rare bug, and i'm sure the unofficial patch guys will fix it