When Cormoran and Robin are chatting late in the evening at the office, Robin closes her note book. In the next shot though it is open again.
Raff has thrown Robin's phone into the canal at Little Venice. Then in the final scene she takes a call on it.
When Robin is driving the Land Rover and her mobile phone rings (private number) whilst Satnav was active Strike accepted the call and the main phone screen clearly shows the silent icon enabled for speaker on the top of the phone screen.