Calendar showing same dates and won't advance every Sunday

Every Sunday something very odd happens to our appointment calendar. I've attached a screenshot. Both weeks show the same dates. When you go to advance a week, the same dates show no matter what. The url is changing so something is happening. This really has me stumped. Below is the shortcode we are using to generate the calendar on the site. Any help is appreciated.

Thanks!

<?php echo do_shortcode('[app_schedule logged="Click on a free time slot to book your appointment." title=""][app_schedule add="1" logged="" title=""][app_pagination step="2"][app_login][app_paypal][app_confirmation address="Address of property to be inspected:" confirm_text="Please continue to confirm your appointment." button_text="Confirm this appointment"]':wink:; ?>