@DEcosse 

Do as you see best, but personally I would not consider a logical application association to be implied by a lower layer network connection. I would, and of course did, restart each of my devices.  Knock on wood no further issue.  But then I'm not watching either.    At a surface level the stuff is working again.  If I see this again, and I suspect I will, I'm going to continue to ask below of TP-Link.

@Riley_S 

@Solla-topee 

To further define my list of "Things TP-Link Should Address:"

1. You almost certainly have some form of client <--> backend "Alive" check.  Doesn't matter details.   What does matter is you should have, and clearly don't, a client side "Restart After ABC Missed 'Alive' Calls".  Something like 3 hours seems reasonable.
2. Similarly, we should have the ability to command a restart.  Even the option to schedule one.  Yes, said device should return to it's previous state.  If not possible end-users should be able to configure what state we want them to enter after a power fail or restart.
   1. Each device "uptime since last restart" should be available on device info screen.
3. As I've outlined in other threads, at least my issues were exacerbated by corrupted Kasa switches.  At the very least many of them had dropped packets, long ping times, and poor reported signal strength that cleared as each device was restarted.   Two even failed to restart and had to reset and rto be reconfigured.  Yet not one non-Kasa device showed problems.   
   1. I don't much trust Kasa network drivers in use and encourage you to consider them as a source of instability.
      1. Certainly something entered many (all?) of Kasa's and only Kasa's  (apparently) into a highly degraded state, and that something needs addressed!
   2. I would appreciate knowing if the Kasa devices participate in some kind of local peer communications among themselves.
      1. If not, would you please comment on how your devices, and only your devices, suffered such group degradation that also cured by individual restart?
4. A summary report from the AP of devices and their IP addresses would be nice.  At the very least that information it should be shown at the "device info" page.
5. I wish you were releasing, at least new products like the KS2- V2, with better Wi-Fi chipsets.   You should at the very least be deploying 802.11 AX chipsets and implementing MU-MIMO, honoring minimum RSSI calls, and using beamforming. I understand the need to remain on 2.4, but believe its irresponsible to continue to use that band as poorly as "N" does.

I have reboot 3 times over the last few days, when the problem was evident - and after all three reboots, both apps showed the devices populated correctly and then it appears to remain 'good' for some time until the next critical failure.

Again, I'm suggesting that the reboot is not so much re-setting the local wifi connection to the devices, (which as shown earlier, appear to remain connected locally while the problem is evident in the Apps) but rather it is re-establishing the outbound connection to the TP-Link server.
@dafish I think you're focussing on me suggesting the reboot is re-establishing each device local connection and I don't believe that is the mechanism. 

The same thing obviously would happen with your suggested whole house power cycle - the router would obviously reboot as well as un-powering/re-powering the devices. 

Rebooting fixed it, but screws other things up. These programmers optimize things for their products without regards to others. I wish Apple made these things, then just like Mac OS on Apple hardware, it would work as it should. Anyone try these Kasa things on Siri?

  @Riley_S I downloaded the beta app. At first it worked and only 1 switch was offline, but when i went back to the app a few minutes later it showed 15 switches offline. When physically came up to those switches, they did not show being offline. 

  @dafish 

I checked the app (both regular and beta) before leaving the house and all were online.

Later at the office, several showed offline.

There has to be some type of remote control setting or feature that I cannot find.

i found *most* of my switches and dimmers went "offline" in the app.  i had to go hit the little "reset button" to the bottom right of the physical switch and they each came back online.  rebooting the router didn't fix it.  i have found in the past that i would get an "occasional" device offine, and rebooting the router DID fix those, but this is some different issue.

i am still having major troubles with the "spot free" cameras and hubs. i removed them, re-added, and still showing offline.

EDIT: the beta app worked fine, was able to see the hub online and re-add the camera

EDIT2: i deleted the beta app and went back to the normal one, all is STILL fine...  beta app reset something or who knows

  @rmhart 

Sir:

Kasa has so far answered exactly none of my questions, so I don't know what I need to know.   For what you are saying to be possible their applicaiton would have to talk peer to peer to the switches.  Certainly possible, and explains why I had what looked like a Kasa only broadcast storm on my network, but again they aren't answering my questions, so..

So if they talk peer to peer, then yes iwhat you are seeing is possible.   On the other hand if the app is only talking to the backend, and the backend handles command and control, then hehavior would be identical local vs remote.   Assuming of course you didn't have a firewall at work stopping you.    Which is certainly possible.   Why they/it would be blocking traffic headed to AWS hosts isn't clear, but none the less possible.

Shame I don't have a wireless analyzer here.   Any my firewall logs don't show local to local traffic, so...

I can say this:

* If I connect my tablet to my phones hotspot, and force my phone into cellular connection, everything continues to work exactly as expected.  This means my tablet should be talking through the internet.  While based only on testing, my testing does suggest the app does not talk directly to the devices.  I'll take them both next time I'm out  and see what I see, will let you know.  Meanwhile, consider going to some store that has public wifi but is not running much of a firewall.

*  My phone, still using the old version of the app, is a disaster and has no F'n idea what's going on in the house.   Nothing works correctly from it.  The beta version on my tbalet is showing status correctly and everything works correctly.

@Riley_S 

It's not popular, but my experience continues to show the app was screwed up and, in my case, the kasa devices where deprecated, several needed full reloads, and eac Kasa required a restart.  From that moment on I have had what appears to be complete success.  Certainly all Alexa commands work, routines run, devices don't show offline, etc..

Meanwhile my phone still running the old version as a baeline control. remains incapable of doing much of anything.