Vantage premium responsive menu not collapsing

Love the features, just can’t work out why the responsive menu doesn’t always work. The menu only collapses when viewing on a mobile device vertically. As soon as I rotate, the menu expands and stacks on top.

Tried changing the resolution to a ridiculously large size and unchecking sticky menu but weirdly this changed the menu to responsive on the desktop but still not on the mobile screen.

What am I missing? I ugraded to premium already.