I have the default iOS Calendar app setup with multiple calendar accounts - iCloud, Exchange and Google. Whenever I open the app, it shows only one of the calendars. I can select them, select holidays and birthdays, then close the config, after which all calendar events are shown. Then if I close the app, reopen and change to a different date, all the events for the other calendars disappear. This is not workable.
What can I do to get all the calendars displayed, and have the setting saved properly?