Cannot create pull request against an empty repo (BB-3749)

I'm very new to git and bitbucket, so I may be doing this wrong, but I'll go ahead and post my steps:

1. forked and empty repo
2. cloned the fork to a local repo
3. committed initial code base to local repo
4. pushed commit
5. clicked "create pull request" – this is where I get the following error: Oops! An error occurred.
   We've been notified and we'll look into the problem.

Is this something I'm doing wrong or a genuine bug?