Currently when a commit is made on the branch, the PR loads and it pulls them from branch. Hence when a branch is deleted PR won’t have reference to it. It will be good to have a way to ensure the commit is referenced on a PR and should not be removed even when branches are deleted.
Error observed:

{
  "type": "error",
  "error": {
    "message": "The source or destination could not be found."
  }
}

He wants a way to ensure the commit referenced on a PR should not be removed even branches are deleted etc