There are other threads for both of these issues, but they are old an locked, so I cannot reply...

So, The long story: I bought 4 (2 packs) of HS210's, two I'm using as regular one-way switches (and they work fine) and two in two different 3-way circuits with regular 3-way switches at the other end - both ends are in the same boxes with each other at either ends of the kitchen (i.e. 2 Kasa switches in one box and the two passive switches at the other end of the room).  Well one switch setup worked fine and dandy, but the other 3-way circuit did not.  The manual switch-overs turned the bulb on and off fine (both ends) but the LED bulb still glowed slightly when OFF and the 'smart' part seemed to be very confused.  Each time I turned the bulb on/off with Alexa, it would act like a toggle (had to On and Off to turn on, then On and Off to turn off again.  Lastly, the little white circle light on the switch would go on for about a second, then off again, every time I pressed the switch.

I re-checked the wiring multiple times, at both ends.  I even switched the Kasa's over between the two pairs of travellers and the problem followed the circuit, so I knew that Kasa switches were OK.  Got my multimeter out and found that both travellers had 90-110 volts on them no matter which way the circuit was set.  Huh?  UPDATE: I mean here that the 'off' traveller had 90-110V, the 'on' traveller had ~119V.

Finally, I had the brilliant idea of changing the LED bulb - one of those "Edison" filament LEDs - with a regular incandescent one.  Result? SUCCESS!! I just about smashed my head on the concrete in frustration.  So it seems that some efficient bulbs don't pass enough current for the Kasa to determine if it's on or off, hence the 'smart' confusion.

Summary:  If you have a similar weird issue and have checked your wiring, try changing the bulb(s)!