Month navigation reverts to original full page load html

Navigating the calendar by month reverts the appearance of any events to their status when the calendar page was first loaded, any changes made by dragging events about appear to be lost.
I say "appear" because the event nodes are actually updated, but they are represented on the calendar in their pre updated state.

To reproduce this do the following:

1. Create an event to display on your calendar.
2. Display your calendar in month view.
3. Move your event by dragging it.
4. Event is now saved.
5. Use the previous/next month navigation to change displayed month.
6. Use the previous/next month navigation to change back to the original month where the event is displayed.
7. The event now displays at the time/date it was originally at before you moved it in step 2.
8. Reload your browser, the event now displays at the time/date you moved it to in step 2.

This behaviour is particular to navigating by month, you can do any calendar navigation, change displays, move fwd and back days and weeks and it all works perfectly. It is not until you try and move back and forward months that the events appear to revert to the state they were on last full page reload.

I'm using fullcalendar 7.2 beta3 with the most recent fullcalendar library on drupal 7.12. I've tested in a fresh minimal d7 env and can consistently reproduce this.