Commits added to a pull request by rescoping sometimes don't get linked to the pull request

Issue Summary

When pull requests are updated, the system stores metadata that associates the commit and the pull request (see BSERV-3574, released in Bitbucket Server/Data Center 5.11). When viewing that commit on the repository "Commits" tab, it will show the pull requests it's associated with, if any.

However, in certain scenarios, new commits associated with an existing pull request do not have that metadata link created. They still show up on the pull request's "Commits" tab, but when viewing the commit from the repository "Commits" tab (left sidebar) or retrieving pull requests by commit via REST the pull request will not be included.

Steps to Reproduce

1. Create a pull request between two branches
2. Add a new commit introducing a merge conflict with the target branch
   • This step may not be necessary
3. Add a new merge commit resolving the conflict

Expected Results

Viewing the merge commit on the repository's "Commits" tab or looking up pull requests associated the merge commit's hash via REST should show the pull request.

Actual Results

The pull request is not shown.

Workaround

There is no workaround for this behavior. It requires a software update to fix, and the fix will not be applied retroactively to existing pull requests.