Transfer announcement in the middle of a call

[3000]

I have recently setup the 3CX PBX and already have a small number of users on it using the 3CX soft phones. One of the users has a problem everyday where she will be on a call speaking to a patient and a female voice will suddenly say "Transfer" and then a dial tone is heard for about 5 seconds and then the caller comes back. This doesn't happen on every call and none of the other users have experienced this, i have given her a new profile, re-installed all the software and even changed her keyboard (last resort), any thoughts or ideas would be gratefully received. :S