Cameras go out of focus, freeze then go black and repeat every minute.

[Gatordog]

I have two Google 2nd Gen outdoor battery cameras running off electric plug-in; one is front of house, one is back of house. They used to work perfectly, but after a year of installation, now, they will go in and out of focus, freeze up and go black for a few seconds. They keep going through this cycle continually. I have a 2nd Gen Google HUB, a Samsung Galaxy Tab S8+ and a Google Pixel Pro 7 cellphone to view my cameras; the tablet and phone use the HOME app. This problem shows up on all the above devices, so it must be is the system or cameras. 

[EmptyNester]

I think your best bet for this kind of issue is to open a support ticket and actually speak with a google tech person.  what your describing sounds like the camera has failed and they might replace it under the warranty.

Here is the link to get you started:

https://support.google.com/googlenest/gethelp