I've installed the Kasa HS210 switches---one at each end of a 4-way setup. Everything seems to work fine except that most of the time the app and sometimes the switch wrongly identifies whether the lights are on or off. In addition, somtimes I have to double tap the app to turn the lights on/off. What I mean is, I tap on the switch in the app and in the app the graphic changes from off to on, but the lights themselves don't turn on. Tap again, app changes from on to off and the lights turn on.

I'm fairly certain I have everything wired correctly, it's just that the app (and therefore google home) doesn't quite know what's going on.