Unable to upload new version of add-on

I’m trying to upload a new version of my add-on to AMO. When I upload the XPI file, it gets validated, but when I click “Add Version” nothing happens (or nothing appears to happen). When I click “Add Version” a second time, I get a message telling me that version has already been uploaded. And then when I go to view all versions, the status of that version is listed as “0 files” and I can’t delete it.

Am I doing something wrong or is this a bug?

This is a server bug. Try uploading again with a new version number. If the problem persists, please file a bug report here.