Halaxy provides the appointment details whenever an external calendar makes a requests for it; unfortunately, it is reliant on the external calendar to make the request for the information. Some external calendars do not do this frequently. There is not much we can do; however, we are looking at other ways to integrate the calendars.
In the meantime you can try deleting your synced calendar in your external calendar (such as iPhone, Outlook, Google or Mac) and requesting a new calendar link in Halaxy. You can then update the external calendar with this new one and see if that makes a difference.