Hi Lutz,
I want to make sure we’re talking about the same issue. Let me further explain. On touch devices, you should be able to tap the top level menu item. It will not navigate to that link, but instead reveal the submenu. You should definitely be able to navigate to any of the submenu items. It is true that you won’t be able to directly navigate to the top level item from touch navigation. This is because the touch interaction replaces the hover interaction.
As a UX best practice (especially considering touch devices), it’s usually better to reserve the top level menu item as just a toggle to reveal additional links. Take a look at Stripe for example, and how they handle clicking their top level items: https://stripe.com/
We have a feature request open to make the menu expand from the indicator, but this could lead to frustration if you accidentally tap the link instead of the icon. You could also have users who just click the link and never realize there’s additional content.
If this isn’t what you’re describing, it could be a different conflict. In that case, would you mind sharing a URL to your site so we can check this?