Bookings calendar offering unavailable times

I have setup a shared booking page for a single user. Set the business hours for 8-5, set the service for 15min buffers on either side of a 30min meeting. User has updated their work hours in their Outlook hours. We have confirmed their machine is set to the correct time zone and their Outlook account online shows the correct time zone. The booking calendar keeps offering appointments for 5:15pm when the last possible appointment should be 4:30pm. 

 

Where else should I look?