If there was a bug that reset the camera's IP to the original default, and you have multiple cameras that all experienced the same glitch, then they will all fight over the same original IP address and have IP address conflicts thus seeming to keep "going offline and online every 10 seconds". Try disconnecting every camera from your switch and only plug one in and see if it gets that original IP and stabilizes. Then you can update and change the IP back and do this one at a time. It's just like if you buy 5 new cameras you can't plug them all in simultaneously to configure them, you have to do it one at a time because they are all fighting for the same ip. That's my theory anyway.
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