Calendar defaulting events to new event

We are a very small business that uses calendar to sync schedules to several phones and computers. The iMac of the person most responsible for entering new events into the calendar is not entering them correctly if the calendar color code is changed, instead reverting them to a 9 AM New Event. Our current work around is to create and save the event before editing it which seems to avoid the problem, but this needs to be fixed. The other computers on our iCloud don't seem to be exhibiting this problem, however one of our iPads seems to. Any ideas?