I've had this issue going on for awhile.

I've installed a LOT of Kasa switches, 58 of them, of all kinds.

All successfully completed install.

After a period of time, over a few days, four of them showed offline on the app. All of them show rapidly blinking green WIFI icon and white circle.

If I press on, they all turn on and off (80-100 times a minute) the attached lights. Nothing will stop the blinking lights, pressing left reset for 15 seconds or longer,  or right reset-to-default for 5 secs, 10 secs, or longer. On some unpredictable occurrence, they will suddenly show they are connected, solid white circle.

All of them are well within the mesh internet.  Switches much further away or right next to them all work flawlessly.

The ONLY way to stop it is to remove the switch.

I did that with two them and reinstalled dumb light switches.

Before I remove the last two (on rarely used lights), I want to see if this is a fixable issue others have solved.

All the lights in the house are LED, builder installed.

One switch is to two sconces in the bathroom, and the other is to to sconces outside on the back porch. Different circuits on the breaker panel.