Microsoft To Do no longer syncs with Planner

For some time, I have used To Do on my Windows 10 laptop as a quick look at what is assigned to me in Planner.  In the last couple of weeks, changes made in Planner never get to To Do, and if I mark any task in To Do as complete, it never gets back to Planner.

If I use To Do on the web the sync is perfectly functional so the issue is apparently with the desktop app.  Is this a known issue and how do I fix it?

Thank you