Custom Agenda Theme Error When Navigating

I was able to successful edit and create my own adapted theme. However, when the end user changes the date, month, or category, it goes back to the default theme. I have some elements hidden via CSS, which persists, but I have changed the formatting within the them and it reverts to the default when navigating. It almost seems like the JavaScript is override the them and re-creating the default on the fly. Please help.

https://wordpress.org/plugins/all-in-one-event-calendar/