[Plugin: Events Calendar] events not initially showing

Hello! We recently installed Events Calendar. Although the admin side of the app works extremely well, we’re having issues with the large calendar front end. Please see:
http://www.sjlc.net/calendar/

When the page initially loads, events are not displayed. However, if you navigate to a different month and then go back to the original, all the events appear. What is causing this?

Thanks for any help available!!!