we know that disabling the “block animations css animations for gutenberg blocks” plugin makes the issue go away, but it’s not clear that means it is responsible for the problem.
we’ve posted to their support about the issue also:
https://wordpress.org/support/topic/mobile-page-can-scroll-right/
we know if we don’t use those block animations on a page (like the contact page) we don’t have the scroll right issue.
but if we load a page with animations and then simply open and close the generatepress mobile menu, the issue doesn’t happen.