I hope you are well today and thank you for your question.
I have tested it on my test site and it’s working fine for me using the latest version of the Jevelin theme.
Could you please try changing it from the below path?
Admin Area -> Appearance -> Theme Settings -> Header
Could you please share your site URL where it’s happening so that I can troubleshoot it?
Solution for this topic
It seems you are using a custom header template on your website and you can disable its sticky header functionality by editing the header template as shown in the attached screenshot.