I have not tested on iOS. Can run with --args="--disable-features=InterestFeedContentSuggestions" to force Zine instead of Feed. Scroll position seems to restore very well when Feed is used.

It would seem that Zine stores some scroll position information when an article is opened, but not when a most likely / explore sites tile is opened. The interesting thing is that this scroll position information gets used even when navigating back from a most likely / explore sites page!

1. Open NTP
2. Scroll all the down, open the 10th article on the screen
3. Navigate back to NTP
4. Scroll up, open explore sites tile
5. Navigate back to NTP
6. Notice that the NTP is scrolled all the way down to the bottom of the screen.