Thanks, Ashok. I am at my wit's end on this. Another aspect -- it's completely unclear to me how/when changes go into effect when they do work. It's certainly not immediate. Today, I had filed a change to the schedule that would have allowed him on, including the current hour + the next 3. In the UI, the changes appeared to be saved as requested. But it did not allow his computer on the network. I told him to put the computer to sleep, since when it awakens from sleep it either renews its DHCP lease or asks for a new one. But sleep/wake did not do it. Nor did a restart. At that point, he was stomping away, and understandably upset, so I did what I know works, which is to delete the device. And that's what prompted my earlier message today.
Here's one piece of information that may or may not be relevant. For some reason, this device (a desktop PC) comes up in the UI now as "tylers-laptop" which it isn't. This one is an ethernet device, and has no wifi. He has another computer which *is* a laptop, and which has the name "tylers-laptop." The desktop *used* to come up with a semi-random name; I assume it's the one Windows assigns by default on install. But in your UI, I have generally been renaming the device to "tylers-desktop." I am inclined to think this isn't important, because the problem doesn't generally occur on the first or second edit, but not long after that. I also confess that I sometimes have changed other fields in that screen -- like changing the idle timeout, or whether it's a kids device or not (though I am totally unclear where, if anywhere, that comes into play anywhere else). I do also generally have it set to always inform me when the device comes and goes from the network, so I can at least look back and see when he was on the net.