Dozens of SSH keys appearing in my Stash user profile

I'm a Stash and Bamboo (5.7.2) admin in for our organization. We have a around 150 repos and about 500 Bamboo plans. We have Bamboo and Stash connected with an application link.

Recently I looked at the SSH tab of my own user profile and noticed I had dozens and dozens of SSH keys. One was for my development machine (which I added long ago), and the rest had a label that is the base URL of our Bamboo instance. Each of these keys seemed to be different.

Later, I discovered that every time I log into Bamboo and add a new "Repository" to a plan (using the "Stash" repository type and selecting the repo and branch from drop-down lists), it adds another SSH key to my account.

To me, this doesn't make much sense. I check the account of another admin and they also had a pile of SSH keys with the same label (from the Bamboo plans they had created).

Is this expected behaviour? It seems really strange to me. What happens to all these plans if one of the admins leaves the organization? Why would setting up a Bamboo plan linked to a repository create an SSH entry for the user that created the Bamboo plan?