Is it (1) the home page news.google.com that exhibits the problem, or is it (2) the individual AMP news pages?
If #1 then the problem is completely unrelated to AMP it's just a subpar js scrolling engine that they decided to use on Google News. If #2 then that would indeed be an iOS-specific issue because on Android AMP pages are just using native scrolling to my knowledge.
I don't remember the last time I went to news.google.com, I see it on news results suggested at the top of the page after I do a normal Google search.
As I said, I wouldn't be surprised if Google was adjusting scrolling settings on iOS (using CSS or JS or something) to make it 'feel' more like Android, since that seems to be their MO recently: make everything feel like Android, not the native platform. Same way they apply material design to all their iOS apps instead of doing things the iOS way.
I hate it. All you did is make your software feel wrong and thus broken.
I know all the "It's more consistent if you switch between platforms" stuff. Switching between OS X and Windows never bothered me, and I don't use other platforms much so that benefit doesn't apply to me. I only get the downsides.
If #1 then the problem is completely unrelated to AMP it's just a subpar js scrolling engine that they decided to use on Google News. If #2 then that would indeed be an iOS-specific issue because on Android AMP pages are just using native scrolling to my knowledge.