Part of Menu Item Hidden on Header Menu

It’s because you’re skewing the parent container with CSS transforms.
You can see in this screen capture of developer tools that the parent cuts off the content on the second row.
Skewed Parent

Try this:

.menu-primary-menu-container{margin-right:10px;}

You’ll see that fixes it, so you just play around with those settings and get it exactly how you want it.

Here’s what happens when I add that rule in the developer tools:
enter image description here