Failing spec on `master`

See https://gitlab.com/gitlab-org/gitlab-ce/builds/6036000

  1) API::API GET /projects/:id/labels returns all available labels to the project
     Failure/Error: expect(json_response.map { |l| l['name'] }).to match_array([group_label.name, priority_label.name, label1.name])

       expected collection contained:  ["bug", "label1", "label6"]
       actual collection contained:    ["bug", "label1", "label4"]
       the missing elements were:      ["label6"]
       the extra elements were:        ["label4"]
     # ./spec/requests/api/labels_spec.rb:32:in `block (3 levels) in <top (required)>'

Finished in 16 minutes 16 seconds (files took 22.58 seconds to load)
584 examples, 1 failure

Failed examples:

rspec ./spec/requests/api/labels_spec.rb:16 # API::API GET /projects/:id/labels returns all available labels to the project

Locally I'm unable to reproduce it with Postgres.