Board View Missing for "My Tasks"

By tenant administrator I meant the person who administers your M365 system - the Global Administrator.  The message center is also available to anyone who has Global Reader role.  For details of the Message Center to Planner sync see https://learn.microsoft.com/en-us/Connectors/m365messagecenter/ I can understand your concerns at only getting one warning, but with dozens of new messages across all of the M365 products released every day, if we repeated them then this would increase the burden on the Global Administrator.  By triaging these changes in Planner, and maybe assigning to other people who 'managed' the different applications this shares the load.  The reason it was stopped was that we released a new UI for Planner and had to make decisions about what made it into the initial release.  If we'd tried to fit everything in, then we wouldn't have anything to release - even early next year.  The choice of which things made the cut we used usage data, and unfortunately it can be that a feature that may not be that heavily used globally, is critical to some customers.  Again, my apologies for the inconvenience here.