In tobacco farm. The plants regenerate over time. Someone must have picked them just before you entered.
No, actually they are bugged. They don't regrow.I put blockers around one tobacco and left it overnight to confirm it.
It would be nice if the tobacco plants in encounters gave you tobacco, not apples.It would be nice if you could craft a pipe to smoke tobacco with instead of having to use the only tobacco rolling machine in the wasteland.