I have exactly the same problem as mentioned here when I log in.
When I log in, I'm always redirected to a workspace to which I had access in the past but do not have access anymore. This results in the error message "Resource not found".
When I go to https://bitbucket.org/account/workspaces/ I see the workspace mentioned, but pressing "Leave" will result in the error message "Resource not found".
I can bypass by directly going to ttps://bitbucket.org/workspaces, but the next time I log in it redirects me to that same workspace again.
What can I do to resolve this?