Something weird's going on on #7 (Orange). You can't pick up a Sentry Gun if you place it on that ledge, just inside spawn. A Dispenser, Teleporter Entrance, or Exit works fine, and you can still pick up a Sentry Gun if you don't place it in spawn, but if you do, it just destroys itself.
This is new with the MvM update, attempting to carry a sentry into a spawn room, will destroy it in MvM. Looks like this applies to all servers.
