Hmm, am I the only beta tester? Anyway, I noticed an unexpected behavior (intended by you or not, I don’t know). When using on mobile, after tapping “Menu” to open the menu, if that’s all one does, the menu stays open until you tap again to close it (that’s what I would expect it to do, since it is a “toggle menu”). But if you then tap an item that has a submenu and the submenu opens, you only have a few quick seconds to decide what to do, or the whole menu will close up on its own! Is that intended? It seems quite inconsistent – the behavior should be the same – either have a timeout or not (I would prefer not, since you still have the toggle button available), but it seems bizarre to have a timeout only if a submenu is open (that affects the whole menu, not just the submenu).
And if you plan to have a timeout at all, I think the time is way too short – I don’t know how many seconds it is, but the person to whom I was showing the site felt rushed looking at only two submenu items – imagine if there were half a dozen or more!