GitLab not sending notifications to merge request approvers.

I have written an entire software development course, and until recently we've been using Bitbucket. I recently rewrote the course to use GitLab instead, mostly because in GitLab the username isn't tied to a particular email like Bitbucket. I had heard good things. But I'm running into problems already.

The first is that merge requests (what the other hosting services call "pull requests") are not sending out notifications to approvers. We just had the lesson where I taught my students to create merge requests. I had them add me as "Reporter" to their projects. Then I had them create a merge request, and add me as an "Approver".

Yet I received no email notifying me that two student had created merge requests with me as an approver on each. I double-checked, and my global notifications are set to "Participate".

I reported this in a comment to a GitLab ticket, but received no response.

So as a workaround I went into my GitLab nofication settings and set the notification level for each student repository to "Watch" so that I (in theory) should be notified of any activity at all. Sure enough, I was notified when my students created merge requests.

Unfortunately even with a notification level of "watch", I was not notified when a student updated a merge request by making a new commitment to the branch and pushing it to GitLab.

Am I doing something wrong? Why am I not getting notifications of merge requests on which I am approver—not even when I'm watching the project?

I've even opened a question on Stack Overflow and put a bounty on it, but I can't get any response.

If I can't get this simple, core functionality to work I guess we'll switch the course to use Github, now that they introduced private repositories.