drchrono does not automatically move appointments, but sometimes it looks that way in large practices as a staff member may accidentally move an appointment from the website or the iPad.
Here's how you can check if someone within your practice moved an appointment
1. Go to Clinical > Audit Log
2. You can refine the search by the patient name, the username you're looking for, and the date range
3. You can see from this log that the user vonShowers changed the patient's appointment from 5/3 to 5/4