It’s been a long time since your post but I thought I’d reply as I’ve solved this issue. Create a new level to serve as a main menu. Your game loads into it, creates the main menu (in level blueprints), then the main menu blueprint opens the first level and destroys itself (redundant).
So Main menu level has the level blueprint, All your other levels do not.
It seems that the issue was that you would load the first level into the main menu, then the main menu would load the level again, which would create the main menu again. Hope that helps anyone else who encounters this issue.