If you set a dropdown element to be multilevel, its behavior doesn’t change. Only its child dropdown elements now become multilevel. I don’t see any way to make a parent dropdown element a multilevel element itself.
This makes it impossible to create a multilevel mobile menu.
Thanks so much for your report!
Can you please show me an example where it works the way you expect it to (independent of bricks)?
From my point of view, the first dropdown cannot be a multilevel because it is the first level. Multilevel means dropdown in dropdown - only then you have several levels.