When a project is deleted in OnDemand, it'll delete the corresponding Confluence/FishEye/Bamboo project, but it seems that in the case of Bamboo the project still hangs around (the plans are removed though).

I don't think this causes any problems, but it does cause customer confusion - a customer raised a support request about the supposedly deleted projects still showing in the "Remove Plans" page in Bamboo admin.

Workaround:

send a DELETE to example.atlassian.net/builds/plugins/servlet/studio/project?key=FOO where FOO is the project key.

If that failed, try to send a DELETE to example.atlassian.net/builds/rest/capabilities/aggregate-root/bamboo.project/FOO.