Hi there.
It seems like drones (sometimes?) won't be despawned when they are on their way and you remove their depot. I'm not sure how to remove those drones. Cannot pick them up. Cannot desctruction planner them. They won't return to the depot. A new requester with the item they are carrying does nothing either.

I have had a few show up in a Generic storage box, but that has happened. very rarely for me.

Okay, I have tested around a bit, and found that I was wrong about a new requester not working. It does work.
Sadly, the drone is lost this way, but I could live with that. But couldn't the drone empty it's inventory and check if any Drone dispatcher has free space and try to return there?
What I still find missing is a warning of some kind to make me aware that there are stuck drones.

Okay, I have tested around a bit, and found that I was wrong about a new requester not working. It does work.
Sadly, the drone is lost this way, but I could live with that. But couldn't the drone empty it's inventory and check if any Drone dispatcher has free space and try to return there?
What I still find missing is a warning of some kind to make me aware that there are stuck drones.

Orphans are supposed to return to the dispatcher.