Cache expiry does not seem to work

[Paul Emich]

Today we updated to the newest version of confluence and the team calendar add-on. We are now running version 5.3 of the Team Calendars module on Confluence 6.3.3.
One thing I noticed (from the pervious version we were running) is that a new option is added to the "Team Calendar" settings, "Cache expiry".

We have set this value to 1, however, when we now drag-drop a Jira issue to another day the issue gets updated in Jira but the calendar doesn't get updated within one minute. The calendar is always updated randomly, no matter how many times I refresh the calendar.

Is this a bug within the Team Calendars add-on or am I missing out on a setting? We'd like our calendar to be as accurate as possible since we also use this for scheduling the week-schedule for our employees.