I'm having an issue with my HS200 v3 (on FW 1.1.3) switches and KP400 v2 (on FW 1.0.6) outdoor plug where they reboot at random intervals. It is most notable when the lights are on since the relay clicks and the light flickers. It also happens when the light is off though since I can see the status light go solid for a few seconds and then flash until WiFi reconnects. I have 9 total HS200s along with several HS210s and HS220s. 4 of my HS200 are version 3.0 and they all have the random reboot issue but none of the 1.0 or 2.0 units do. I also have a KP400 version 2.0 outdoor plug that has the issue. I have been pulling my hair out for several weeks trying everything from tracing circuits, checking wire nuts, swapping switches, and changing numerous WiFi and router settings; nothing has worked. I did have one spare 2.0 switch that I swapped for one of the 3.0 units. Since the swap, that light has worked flawlessly. I think that rules out any wiring or WiFi signal issues.
One strange observation is that the reboots are synchronized between all of the affected HS200s and the KP400. I have been using the "runtime" feature of the Kasa app to track how often the reboots occur and it looks like they all reboot at the same time but at random intervals. I have even caught it in real time while watching the Kasa main screen on a few occasions. This leads me to believe that it is a software/server side issue.
My network consists of a TP link DOCSIS modem > Edgerouter X router > TP link SG-1016PE switch > multiple EAP225 access points. I have tried disabling fast roaming, disabling 5Ghz, disabling Airtime fairness, changing DNS settings, verified no firewall logs are blocking communication to/from the switches. Nothing seems to have an affect.