Problem with a mobile hamburger menu

Hi there,
I have an issue with my mobile menu. When I open the hamburger menu it extends to the bottom of the screen. See photo 1 for example. However, if I click on the “Practice Areas” again (which is a dropdown) and then close it it works. I want it to look like on Click 3 when I first open the menu. Any ideas why this happens?

Click 1:

Click 2:
Click 3:

Here is my site Read-Only: LINK

When i try it, it opens up as in “click 3”, have you tried to publish the site and then check it out?

It’s published but for me it’s the same problem. On my phone and laptop (with mobile screen size) as well. It also happens only on the first open of the page. After that, it works fine. You need to refresh the page to experience the bug again.