I think I'm misunderstanding something fundamental about deploy keys. Here's the situation.
We have a server set up through Forge. Git repository (private) is working great. Let's call it Repository-A.
Today, I set up a new personal Forge account, set up the server, and tried to copy/paste the deploy key from Forge to my Github repository (Repository-B). I got the message, "Key is already in use" from Github. The Repository-A and -B are managed by the same Github organization account.
I don't understand this at all. I assumed that each server managed by Forge had its own SSH key, in which case, how could a key on a new server already be in use?