Endpoint Manager - Can't Transfer Calls with BLF on Polycom Phones

I’ve just re-provisioned about 20 Polycom SoundPoint IP Phones using the Commercial Endpoint Manager as we wanted to make sure we are running support software.

On a Polycom 670 Phone, with a BEM Expansion pack, the receptionist is no longer able to transfer calls using the BLF fields on the phone. I tried switching the BLF fields to BLF-XFER, but you still can’t transfer calls by pressing the BLF field button on the phone.