Ring Doorbell 2 stops after charging

My Ring doorbell 2 has recently started behaving strangely. It ran out of battery and so I charged it fully and re-mounted. It was working at that point. After about an hour, I tried live view, but got a black screen. I tried pressing the bell and nothing happened. Internet etc. all fine. I plugged it back in to the charger and after about a minute the blue ring started flashing and the doorbell seemed to be working again. It was reporting 100% battery and good internet. Then the same issue happened with it stopping working after a short period. I have to plug it back in for it to start working again, and have tried a soft and hard reset etc. - all the options for resetting the thing. It is still doing this i.e it works for a short period and then just becomes a brick until I plug it back in and reset it. Any ideas? Is it totally broken?