The current behaviour is when someone submit a discussion, and this discussion under moderation, it will notify to your site Superadmin, custom email address or moderators there got a new discussion under moderation.
Once the discussion approved by site moderators or someone else, system will send out email notification to the author your discussion post already get approved by someone.
If you enabled this setting `Notify User for Their Actions`, so it will notify to the author he did created a new discussion on the site, but you are right, by right, the email title should mention something like you have posted a new question but this is under moderation, i will lock this issue into our issue tracker.
For now you can temporary disabled this setting from your backend > Easydiscuss > setting > notification.
By the way, i did a test submit a new discussion via email on your site, it seems like it doesn't generate duplicate email notification, you can check my attached screenshot below.