I've recently upgraded some of our cameras with Reolink PoE 5MP HD cameras, unlike the old cameras these have IR for night vision. I'm now getting multiple false triggers because for an hour or two during the night each of them starts displaying 'cobwebs' on the image, which shake and move enough to trigger recordings on BI. The first morning after this happened I went out to clean away the 'cobwebs' but there weren't any! Is this some sort of refracted light effect generated by the lens? Any other ideas? I've attached an image.