You won’t be able to recreate the problem on your demo, as your pages are not optimised for mobile devices – they simply render as full sized web pages (they are not responsive).
I can’t provide you with FTP access – the fix should be somewhere in the drill down JS. All my assets are compiled (JS/CSS) so this will make things harder.
The bug can be seen when you go to the URL I provided you (this defaults to the english version of the site).
On initial page load, or page refresh, when you trigger the mobile nav on an iPhone or iPad running iOS 10.3+, the div that drill down JS sets a height on, is calculated incorrectly.
In the screenshot above, the height is incorrect by an additional 25px.
If you drill down into a sub menu, or if you click on a link in the mobile nav and trigger the mobile nav again, the height of the div (which is set by drill down js) is set correctly.
If I have just 3 top level nav items, I get no bug. When I add more top level nav items, the bug appears. If I add 20 top level nav items, the bug also appears with a larger incorrect height value.
