[Hummingbird Pro] Caching issue affecting my event calendar


I’m using Modern Tribe Event Calendar on my site.

When using a shortcode to show a calendar for only a specific category eg. Film (https://nac.org/film/) it works perfectly while I’m logged in.

But when logged out, it shows all events regardless of category.

I contacted the event calendar support and they have pointed me towards Hummingbird CDN caching. But even when I deactivate Hummingbird the problem persists.

Is there a Caching at the Host level I can’t reach, and is there a way to prevent the calendar from being cached?