@gkarasik 

Welcome to TP-Link community! I didn’t realize you had started a separate thread. I wanted to make sure you saw my response, so I’m including my thoughts here on why this might be happening and how to address it:

If the bulb turns on automatically after power is restored, it means its default state is set to “On”. If you don’t want it to light up, you can adjust this setting in the app. How to set Default State for Tapo smart bulb

For Tapo smart devices, if they fail to reconnect automatically after a power outage, restarting both the device and your router typically helps. However, if the devices disappear from the app entirely, that indicates a different issue which may require further troubleshooting.

Since you have the smart bulbs, their behavior (disappearing in the app after power is restored) is likely caused by an unstable power supply. When power fluctuates during restoration, it can mimic the soft‑reset sequence (three quick on‑off cycles) that triggers a reset. If the voltage is too low, the bulb may power on internally without visibly lighting up, so the reset may happen without obvious signs. 

Tapo bulbs now include improved handling for unstable power conditions—the reset threshold has been raised to make accidental resets less likely. You can read more about this update and request the optimized firmware via the article linked below.

Tapo Smart Bulb Reset Method Update -- Reducing Bulb Resets Due to Unstable Power Supply

As for your smart switch and other smart devices, their reset mechanism are different from the bulb’s, so the explanation above does not apply. When a device goes offline, it normally stays visible in the app with an “offline” status and is only removed if you delete it manually. If this issue recurs or you’re able to reproduce it consistently (device disappears from the app after a power cut), i would recommend contacting our support team directly for deeper investigation. Contact Technical Support