Why do I keep jumping between items when scrolling in reading list?
I’ve also had this problem. Couldn’t figure out why it was sometimes randomly jumping and sometimes not. Maybe I flick the screen in strange ways? I was able to work around it with this Pythonista script. It reopens the same page in the same tab. Breaks it free from the reading list. So the whole scroll to the end to jump to a different item doesn’t work anymore, but I never really used that, preferring to manually pick the next item. 

From the link:

import appex
import requests
import webbrowser


def main():
    if not appex.is_running_extension():
        url = 'http://arstechnica.com'
    else:
        url = appex.get_url()
    if url:
        webbrowser.get('safari').open(url)
    else:
        print('No input URL found.')


if __name__ == '__main__':
    main()