Closeing a issue via commit from another repo doesn't work

My commit message: End bug track testing, fixes core/corebugs#1

this should close the issue, but it just results in a mention: mentioned in commit core/core@5cab86b093082dfeb344ce05e643d4232036a5b3

I am owner of both projects and they are in the same group. I am also the owner of that group.

Components: GitLab 7.4.3 GitLab Shell 2.0.1 GitLab API v3 Ruby 2.1.2p95 Rails 4.1.1

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