@Crynus I was able to fix it by fully resetting the switch by holding the left reset button under the switch until the lights fully cycled.  Once they cycled i was able to add it to homekit using the normal QR sticker that came with the switch.  If you don't hold it until the light cycles on and off it won't work.

hope this helps!

  @Crynus 

The reset worked for me, much appreciated!  After first pairing with HomeKit, it was really easy to add it to the Kasa app afterward, as I was prompted upon just opening the app.  Seems like adding to HomeKit first is the way to go, thanks!