Editing an event causes calendar to reload and show everything twice

I'm in confluence, click Calendars at the top toolbar. I edit an event adding "who" for an event. Upon completion the calendar reloads and doubles everything. I click Calendars at the top again and it's fine. I've also seen this issue when editing an event and moving it to a new date. It shows on old and new dates and doubles on the new date.

Steps to Reproduce in IE

1. Navigate to Calendars
2. Add a full day event
3. Edit the event and change the date

Steps to Reproduce in Chrome

1. Navigate to Calendars
2. Add a full day event
3. Edit the event and add a user (who) for the event

Actual Result

Upon editing the event, they (Events) will be shown twice. and refreshing the page will fix this.