I think i know the problem:
Under “Appearance >Customize >Menu Plus >Slideout menu” See if you have slideout menu set to both desktop and mobile. If yes, either disable for both or enable it for mobile only.
If that’s not it, i’m afraid i have reached the limit of my little knowledge 🙂
Agressively support the kind of work you want to see. Buy it. Talk about it. Review it.