Ring Doorbell 2 - over night fault

Daytime colour video is fine. When it goes into infra-red at night, the video is erratic and mostly appears with white lines of varying density - if you are old enough, it is how the old cathode ray tube CRT - used to go when one of the valves was on its way out. Here is a an iCloud link of a screen recording of a time lapse of the door bell video. The problem occurs every night - https://share.icloud.com/photos/066S91dLJwfcbn7960wZPy2UQ