What are you seeing, and how does it differ from what you expect to see?
GitHub allows be to configure custom notifications per issue. git - Gitlab: how can I disable email notifications for new commits pushed to merge requests? - Stack Overflow and Sign in · GitLab demonstrate that this is possible per group and project, but I do not see the way to do it per issue.
This is desirable because it allows me to be notified solely when an issue is closed or reopened. I see no comparable option for GitLab, but obviously this functionality must be present. Please direct me to it.
Are you using self-managed or gitlab.com?