I tried what you recommended, changing the PERMALINKS so they are ‘Pretty Permalinks’ but it didn’t fix the problem.
I did more testing and found what might be the ‘root cause’ of the problem.
Our current configuration is a “Calendar” Page that uses the [tribe_events] shortcode to display the calendar:
https://www.dabr.com/calendar/
I tested using the “Events” link and I CAN’T reproduce the problem.
It works fine if I use:
https://www.dabr.com/events/
So, using the shortcode, the date is passed as a query string through the URL:
https://www.dabr.com/calendar/?tribe-bar-date=2017-04
I tried setting the view in the shortcode [tribe_events view=”month”] but it did NOT fix the problem.
If I try to use the /events/ SLUG then I lose my page style control. I prefer NOT using the STYLE option in the SETTINGS of the Events Calendar plugin.
Is there something more specific I can pass through the URL so the shortcode gets the right month?