Shelly 3EM sudden negative consumption on a phase

I have a 3 phase + N installation in my home. I've been using the Shelly 3EM since 30/06 and yesterday evening (09/07), all of a sudden phase B started showing a negative power consumption. Before the shift I had a total idle consumption of about 175W, which remains about the same.

Phase A idle consumption has changed from 133W to 322W.

Phase B idle consumption has changed from 20W to -195W.

Phase C hasn't changed and still shows an idle consumption of 7W.

It seems the negative consumption on phase B gets offset by a higher consumption on phase A

I have no solar panels or anything else that produces electricity.

What could be the reason for this behavior?

Hello All

In a similar way I have a Shelly EM on a L+N installation (I measure both the 16A and 10A line). I installed the unit on the 08 July and all readings were positive. Few days after, all of a sudden, they both changed in negative (maintaining approx the same absolute readings). Few days later again the switched to positive and around one hour ago they became again negative.

I had no direct contact (physical or S/W) with the sensors or the unit and the only thing I did was to read values via WEB interface. I had it connected to Home Assistant till this early afternoon but today, when it got negative, it was disconnected (if that could be of any interest).

Any hint on where to look for the issue would be greatly appreciated.

This is unit is not (yet) connected to cloud.

Thanks in advance.

Same issue here, sometimes i get a positive reading, and sometimes a negative.

Hi, thank you for your reply. I checked, and tried turning the direction of one of the magnets, with no luck, attaching image of problem.