To be perfectly honest then no – I can’t.
I DO see that your WP theme is loading the same ‘mobilemenu’ javascript library as we use. But – I also note that after your WP theme version is loaded the Simple:Press file is not – which is how it should be.
But I also see that your nav menu when the mobilemenu script transforms it, has a class name of ‘spmobilemenu’ which has the ‘sp’ prefix. Where it is getting that from I really have no idea. Nor why it should be visible as I can see no CSS rules causing it to be displayed.
Actually – I see two select boxes on the forum page – one above the site graphic at the top and one below the normal menu.
I will certainly look at our coding but I can already see that your mobile menu IS getting defined by the WP theme scripts and using the WP theme element ID names which should divorce it entirely from any forum page content. The key, perhaps, is finding out what is changing the display status…