How to prevent an accidental merge request from keeping an issue open

We run into an occasional issue that we don’t know how to fix. First the background:

  1. We like to use the Create merge request button on an issue to create a merge request that will then automatically close the issue once the merge request is accepted via the Closes #issueNum feature.
  2. Periodically there are two related issues that multiple developers create separate merge requests for, but it turns out that the fix for one issue will simultaneously fix the other issue, causing one of the merge requests to become redundant and we manual close one of them without ever doing any work on that branch and never completing the merge request.
  3. This process seems to create a case where the issue attached that closed merge request won’t automatically close because that closed merge request keeps it open.

For example:
Take two issues, issue 1 and issue 2. Developers create two merge requests/branches off from them, so now we have branches
1-issue-1-title
2-issue-2-title
One of the developers discovers that fixing issue 1 will fix issue 2 at the same time. So the developer goes in and closes merge request 2, and edits its text to remove the “Closes #2” text from it. Then once they finish the work, they add “Closes #2” to the merge request for issue 1 (so now that merge request says that it closes both 1 & 2).

Once merge request 1 is accepted, issue 1 is automatically closed, but issue 2 stays open saying that it needs merge request 2 to be accepted before closing