The Product team is currently evaluating this issue resolution. When this issue is resolved, it will be communicated in the Product Announcements and not with the Maintenance Updates.
When a user navigates to a calendar, the calendar loads a random date range in the past (e.g., a week from the year 1800).
Workaround
Clicking Today loads the correct week on the calendar.
First reported on April 7, 2020.