Site Map page - doesn’t want to close iOS when scrolling it down

As seen in the video, when trying to scroll to close “Site Map” page it doesn’t want to close. I was able to come out of it by pressing the back button on bottom left hand side of the page only. This problem seems to apply only to “Site Map”. Because as can be seen in the video, I tried scrolling to close “Service Levels” and it worked for that