Shelly Pro 4 PM random change of state on grid micro cut.

I leave in south Italian country side, and the Grid is not the best, ... V fluctuation and Micro cut are frequent.

(large photovoltaic plant, frequent Storm, consumers peak, the grid have hard time to cope with fluctuation).

On several occasions (about 10 times a year), my 2 Shelly Pro 4 PM turn ON or OFF all 4 channels, and I was able to witness and confirm it happen on Micro cut. I also have all sort of Shelly 1st Gen (1, 1L, 1PM, Dimmer) in my place, and none of them are affected. (nor Sonoff/Tasmota item)

It is very annoying, as it defeat the purpose of relays if I have to power off manually the breaker in front of the Shelly Pro 4PM.

Load are sensitive like Under Floor Heating or pool pump and could lead on huge electric Bill if I am not there.

Do you think a hardware solution could solve the problem ? (maybe a capacitor? size ?)

Thank you for your help ...

Thank you thgoebel ,

Some of the channel have physical switch. and are set to match the state of the switch. but obviously that didn't happen because I don't think the ShellyPro4PM actually reboot. (your advice would have been perfect in that case)

I suppose it just lost/invert the 4 register's state* on the micro cut. when it happen, I can see AT ONCE other house lights flicker, server APC bip (server+router +switch protected , Shelly pro4PM are cat5 connected to switch), and some light channels turn ON (Shelly pro4PM).

A reboot would take few seconds, this why I think Shelly didn't reboot. Unfortunately I didn't think to look at the log (Home assistant - MQTT).

ShellyPro4PMState.jpeg

For the capacitor I was more thinking about an external one on the main, on the Shelly power input. (a bit like the one you install on the output for motor) but my electrical skill are a bit outdated...

*I had only witness 4 channels OFF before turning ON after micro cut, (not a combination of state)