Hi all, wonder if anyone can help. I've noticed that several of my cameras are exhibiting what I can only describe as purple noise, when in a dark environment. During day light hours they are fine, but soon as it becomes dark, they start to randomly flash purple (and sometimes red) noise. The attached image shows what I mean.
This is happening on an official 8MP PiCam, and a 5MP Zero Cam. Its happening on a Pi3B, and a Pi3A+
I'm using RPi Cam Web Interface to view, both Pi's are still on Stretch, 4.19.57-v7+
Any ideas what might be the cause?