Hello, @Artur,
I have checked your issue by login into your site and I found that there is no icon set on the menu then I try to add an icon on the menu item to check whether it’s working or not. I found no issue the icon appears fine when I added it. I have made a detail video for you please watch it complete for a better reference to understand: https://streamable.com/ywxoxd
Regards 8Themes Team.