I’m not experiencing the issue on my end. I also went to oz-berger.webflow.io on my phone and no issue there. (It’s possible you haven’t published the site since then but works correctly for me.)
I thought it might have something to do with your main nav overlapping the tab menu since your main nav logo anchors to the top of the page. This doesn’t seem to be an issue but you might try changing your main nav from “sticky” to “Fixed” position. Using fixed will require you to change the nav width to 100%. I’m not sure if this will change anything since I cannot publish the change to view the results live.
I also get mixed results when playing around with your mobile nav.
In the Designer mode, the open menu pushes the page content down but in Preview mode the open menu overlaps the page content.