Meni item disappers Lawyeria theme

Hi I have an issue with WP.

I am adding 8 items into my menu. There is no problem with saving them. But when I am viewing my site the last item of the menu is showing itself only for a 0.5s and then disappears. Sometimes I can’t even see it appears.

When I check source code in browser there is nothing about the last item. Like it never exists. So there is nothing with css I guess.

Can you tell my why this element does not stay there where it should ?

I tried allready adding more items and nothing happens.
I tried desactivate all plugins – no help.

When i am using Widgetize navigation menu plugin I can see one elemnt less – so 2 of them disappears;/

I hope my English is understandable for you.

Thanks for any help.