Automatic closing of PRs on pushed merges is not working intermittently (BB-10727)

Pull requests intermittently do not close automatically as a result of a local merge/push

To reproduce:

• Create a pull request
• Merge the two branches locally
• Push the merge to Bitbucket
• Observe the PR is still open
• Then push a new commit into the repo as another user
• Observe it is now closed, also the person who closed it is the second pusher