Have to check/uncheck/check shared calendars to get them to display correctly.

I have access to multiple shared calendars in Outlook.  In the past few months when I check a calendar to look at it, I will get an error or the calendar will only partially display.  If I uncheck it and re-check it then it displays correctly. When it doesn't display correctly it looks like it partially loads and stops so only a part of the calendar (not just events, the entire calendar) is displayed.

Not sure what could be causing this behaviour.