Disable background vertical scroll

Hello Support

I have a popup height that is greater than the screen size. So when I scroll throughthe content of popup vertically, the content behind the popup moves as well. This only happens on mobile ios devices, everything is fine on desktop. I havn’t checked on android devices but how do I resolve this issue?

If my content is really long, the user will end up at the wrong position of my page after closing the popup.

Thank you