I have had one of these phones for several months now. I have it permanently on answer to screen calls. Something like 1 out of 2 times the phone answers, the caller starts to leave a message, I decide to speak so lift the handset off the base, and at that point it cuts. Sometimes if I leave the phone to take the message it also cuts in the same way so the caller doesn't get to leave any more than a couple seconds of message.
I called the helpline in the instruction book and was told to try to reboot phone by unplugging, leaving it unplugged for 30 minutes then plug in again. This made no difference. The helplin guy asked if I had any electrical equipment near and I do have a wireless router (non-BT) which at the time was only 2 feet away. It was suggested I move it further away. I have it about 4 feet away now and any further would put it in an inconvenient location.
I wondered it the router frequency (2.4Ghz) was the same as the phone and this was the problem. But I aksed elsewhere and someone else had the same devices next to each other on a table with no issues - so it is an interference problem or an actual fault?
One day we had an important call due so we hed to put a good reliable corded anwerphone back in place to take that call whilst out, which it did fine.