I have recently tried a NoIR camera in my new appartment and started getting this strange interference, see photo below. I comes and goes randomly but happens mostly at night in a dark room. Sometimes it can go on a whole night, every minute or so, and sometimes just for minute.
I have used the same setup on a Pi0w and on a Pi2+ before without this problem and I do not think the software has changed.
- Pi3+ with Buster
Pihut Zerocam NOir https://thepihut.com/products/zerocam-noir-camera-for-raspberry-pi-zero
Ribbon cable is extended to 45 cm