I see. I think it's something specific to older iOS versions since it's working properly in my test device. Probably some CSS property not supported or bug :(
If there’s a video (animated gif?) that takes the full height of the display (iPhone 15 pro, but happened on my 12 pro also) then I can’t scroll up or down. It literally gets stuck there and I have to go back to the main menu, which loses my place.
I can tap the post but can’t go up or down to get away from it. So it’s either view the post or go back to the previous screen (menu).
Happens from time to time just scrolling All or whatever.
This is a bug that Apple engineers introduced with iOS 17. Luckily it's already fixed and will be released with an upcoming iOS version. Very annoying, however. :/