Reminders not syncing between devices

For many years, my wife and I have always used a "shared" Reminders list so that we can both make updates/changes to reminders and both be able to see them. A year or so ago something changed in how that worked. Figured out she had to Share her list with me now, which we did, and it was working again, until a week or two ago.

Now, once again, can not get our "Shared" Reminders list to update on both iPhones. Both phones running current iOS and all Applications updated. Have tried, once again, to stop sharing the Shared List from my wife's phone and then Re-sharing or adding me to it, but now it won't update at all. Both phones show the list is shared and that it is my wife's list, but it will not update on either phone when one of us adds or makes changes on the list.

Also, for whatever reason when Apple made a change some time ago, when you are working in Reminders, finishing updating a reminder and hit "Done", instead of just sitting where you were just working, it scrolls half way back up the list. Has done this for some time on different iPhone models with our Shared List. Why can't it just default to right where you were working at and leave you there?