Menu on mobile viewport don't work properly

Hello, I'm using theme Catch Fullscrean free version and I've got problem with mobile menu on homepage view. (http://mamzajawke.azurewebsites.net/) Problem occurs when user enters the site and don't scroll down, so the header is sticked to bottom and there is a featured-slider on the rest of the view. In this position, when the user clicks on menu button - only icon of the menu button changes to "exit", but the menu isn't visible. This isn't the case when a user scrolls down and header goes from bottom to top - then menu works fine. How can I change it, so the menu would work? Additionaly, I would like to change the way of scrolling on homepage - there are sections (these 3 dots with arrows where user can navigate on the site). Is there easy way to make scrolling be more smoothly, without these sections? This is happening only on the homepage, on the other pages there is no such scrolling effect. Thank you in advance.