Booking an appointment from the front end as admin

Appointments+ seems to work fine from a client perspective, no problem (That we can see).

Here is the issue:

#1. Lets say as an admin or service provider I make an appointment from a telephone call, on the front end.

All is ok.

#2. I then take a second appointment over the phone and make a booking via the front end again.

All seems to be ok.

Here comes the problem.

When I go to the back end to check the clients details I find that the last appointment I made (#2.) has overwritten the clients personal details in appointment #1. The actual dates and times and service provider remain unchanged and are correct. this can happen over many many appointments. We have discovered this situation at the end of a very busy day can make it almost impossible to know who is coming for an appointment. The only way we can verify it is by the confirmation email the service provider gets when an appointment is made.
Is there a simple way to resolve this? For speed and convenience using the front end makes sense. Making appointments on the back end is ok, but you have to keep switching from front to back to make sure an appointment is available.