When sticky navigation is on, there is a white space at the top of the screen once you scroll down on the page and then scroll back up. But when I turn sticky navigation off, it covers the course image and other content at the top of the course page. See the page here: https://learn.level360.co/course/one-course/
Go to wp-admin->appearance->customiser->add custom CSS-> add these lines and save.
http://prntscr.com/dcrh1d
.single-course .course_header .container {margin-top: 80px !important;}