@NoActivity 

Here are some suggestions for this situation.

1. Check if the neutral wires from multiple circuits are bundled together and connected to the same breaker, this connection might cause interference.

2. Check if high-power appliances are being used on the same breaker when the light flickers.

3. Try to change a different bulb for that non-Kasa switch, monitor whether the problem is consistent. Or install Kasa switch KS225 under a different breaker, check if similar problem still exists.

4. Perform a dimming calibration for the Kasa switch and reduce the maximum brightness of the switch.