Thank you for the update, Darren. I guess I didn't expect much more to come from Linksys on the issue considering the camera is at end of life.
I agree that the problem is on the camera end as I experience identical timing of the problem on three PCs with three different OSs using three different browsers on each, plus two android devices running an IP Cam viewer app. And a camera reboot restores images and motion sensing email.
My two WVC80Ns have been stable for the past week, so I have not been able to do any further troubleshooting. If or when they become intermittent again, I would like to try replacement power supplies on them. It seems unlikely that both supplies would begin to fail about the same time, and cause both cameras to fail just about the same time, but it is conceivable that a marginal supply could be stressed by a power line dip or bump.
I am in search of similar cameras at a similar price, particularly one suitable for outside use, but have not found one I like yet. I tried a D-Link outdoor camera, but that had issues with all current versions of firmware that caused alarm email not to go out . Reverting to early firmware and they worked fine, but that produces a firmware version nag screen on mycloud.com. That one went back, so I'm still looking.
Linds