O365 group calendar not updating

I have a user who was the only person adding to a group calendar that was used to show time off requests.  items were showing up so all members could see the request.  

recently, 2 others members have been tasked with entering these requests on to the calendar.  when they add the request to the group calendar, everyone can see them on the group calendar except the original user.  She only sees them in her personal calendar.  

What would cause this to happen?  she wants to see the requests only on the group calendar, not her personal calendar.