I had this issue with the free version and reported it here: https://wordpress.org/support/topic/url-slug-stopped-working-with-4-6-5/
I’ve now upgraded to Pro and would very much appreciate your help resolving the issue. Basically, any view aside from Month (List, Week, Day, Map) results in a 404 if there is no data (future event) to display. This was working fine and I am not sure why it stopped. I’ve tried flushing permalinks (many times) and unchecked the “Use Javascript to control date filtering” option. I then disabled every other plugin I had active (leaving only The Events Calendar) and removed all css and custom functions. Nothing changed. I’ve also created a test site with a fresh install of wordpress and the theme I am using and, in that case, the view loads and I get the expected no results found message. I’m stumped. Please help. I am very close to launching my site and need to resolve this before we go live.
WP 4.8.3
Themify Ultra theme
Not working:
https://wordpress.opendrives.com/events/
Working test site with same WP version and theme:
https://themifyclean.opendrives.com/events/
As an aside, I just noticed the logging option on the Help page and set it to full. Now my entire Help page is blank.