@TP-Link 

Please see below:

1. Did you use the Homebridge to manage the home devices?

          No, I do not use a bridge device

2. If the home router supported guest network, please connect the smart plug to guest Wi-Fi and check again whether the auto rebooting issue continues;

          I have a sperate WiFi network for all my IoT devices. I did try making that network a guest network but it did not help.

3. After resetting KP400 and HS200, then please do not set it up and leave it un-configured; would it automatically turn on and off again?

          If I just reset them and without going through setup, they do not randomly turn off/on

Since my original post, I have found a partial solution and suspected cause. I have created another WiFi network dedicated to my TP-link switches and plugs. I also had to make it a guest network. The strange thing is that everything behaves correctly now, except when my phone is connected to this network (i.e. when setting up a new device). Every time I switch my phone from the main network to the isolated light network, the HS200 and KP400s start acting up. Once I disconnect my phone, everything goes back to normal. I suspect that is has something to do with the Kasa app trying to scan for devices or something but have not investigated any further. 

I'm having this same issue. Any resolution?

I am also having the same problems with my HS200 v4.0.  In fact, I have already replaced one HS200 with a new one because of the rebooting issue.  This problem has existed with both switches, so I'm pretty sure the problem isn't with the electrical wiring. 

@riwall @Brook @TP-Link 

This is just started happening to me.

I've had multiple TP-Link Kasa devices rock solid for 1+ years and now random reboots across the board (the time of reboot is random, but when it happens, all devices do it at the same time). This is extremely annoying because a reboot issues a power cycle so lights flicker and plugs go off and back on.

What changed? The wireless network is now run by a TP-Link EAP245v3(US) - single, no mesh instead of an old Asus router.

I tried changing channels, forcing 20mhz, 40mhz, all other features are default: steering, fairness and beamforming off - reboots continue.

I put them back on the Asus router and no more reboots.

All other devices are behaving as expected on the TP-Link AP except the TP-Link Kasa devices - how ironic.

So I don't think the Kasa devices are the problem, I think it's the EAP, even without mesh / hopping.

I wish there was a way in the Kasa app to tell devices in advanced settings to log to a remote server so we can see what errors they are getting prior to deciding to reboot.

If TP-Link can send me a beta firmware for an HS103v2(CA/1.0) which supports local access and remote logging and let me know which command to send to specify the remote server, I can help debug this problem.

Same with the AP - I can debug - It can already push logs but there's nothing useful so likely I'd have to enable debug remote logging somehow, ie via SSH.

@FSF 

Did you see my post above about a work-around? 

Since my original post, I have found a partial solution and suspected cause. I have created another WiFi SSID dedicated to my TP-link switches and plugs. I also had to make it a guest network. The strange thing is that everything behaves correctly now, except when my phone is connected to this network (i.e. when setting up a new device). Every time I switch my phone from the main network to the isolated network, the HS200 and KP400s (and now KP103s and KP115s) start acting up. Once I disconnect my phone, everything goes back to normal. I suspect that is has something to do with a combination of the Omada APs and Kasa app trying to scan for devices or something but have not investigated any further.

@riwall 

In my case, iot devices were already on a separate network. When introducing the eap, to avoid changing anything on the devices, I disabled the iot SSID on the router and enabled a new iot SSID with the same password on the eap. All devices jumped over and were accessible as expected.

Then they started rebooting randomly throughout the day but together at the same time (HS103 and HS200).

Disabled the SSID on the eap, enabled it on the router, and everything was fine again. I tried this multiple times with the same result.

I’m having the same issue, however I’m also using homebridge to automate and integrate with HomeKit. I tried leaving everything on the same subnet as is, and tried logging out of Kasa smart app on all our home mobile devices, but still got the random restarts :( I dont mind creating a segregated vlan for my iOT devices, however gonna have issues with homebridge unless i open the ports between the subnets, which from what i gather i will have the same issue again. I’m gonna try few more things, but I’m thinking I’m gonna have to return all my switches back to amazon. I bought crap load of switches to automate my whole house, so its bit disappointing as i love the look of these switches. Gonna have to try another brand…