Environment: phosh 0.17.0-1pureos1, mobile portrait view, 720x1440, 200% scale, Epiphany 40.2, webkit 2.34.6.
Websites like: https://www.washingtonpost.com/world/ukraine-russia/?itid=nb_war-in-ukraine
Steps to repeat:

find webpage and select links to navigate forward to a page with scrollable content optimized for mobile screen, see link above or similar,
use touchscreen finger input to scroll up and down on page by swiping up and down,
observe that but the slightest horizontal movement from left to right while scrolling, it is incorrectly interpreted as a swipe to the right,

In the above case a right swipe exposes a menu panel on the left, for other websites it causes the user to navigate back to a previous webpage.
What it should be doing when the finger is traveling a longer distance vertically than horizontally is to scroll up and down and not swipe left or right (or vice versa). In other words it should be more sensitive to scroll up and down, and require less sensitivity and more distance or speed traveling left right to swipe instead of scroll.
Notes: on pages like https://gitlab.gnome.org/GNOME/epiphany/-/issues/1761 it is not sensitive to the above issue and functions properly, so its only related to certain web elements or pages that cause this behaviour.