Unable to add existing deploy key to project

Summary

I'm unable to add a deploy key to project A when that same deploy key is already added on project B. This made sense since we've shared a hosting environment (with the same account and the same ssh key), but it was a different project with a different person who made the project. This happened on the public gitlab.org website, so I can't make the key globally available.

Steps to reproduce

• Generate a SSH-key.
• Add this key to a project A, that belongs to user A.
• Add the same key to project B, that belongs to user B. They are not in the same group. An error occurs stating that the key already exists.

Expected behavior

I would expect for the key to be successfully added to the second project also. The same key should be able to be added to two projects.

Actual behaviour

It doesn't.