I have the EasySolar-II 48/5000/70-50 MPPT 250/100 GX installed on an off grid system. The input of the public electrical network connects to a differential circuit breaker, from which a cable goes to the inverter. Then comes an inverter cable that plugs into the main frame of the house. I have a shelly EM measuring the consumption in the phase cable that comes from the public power grid, but since I installed the inverter, it started to give me strange values, sometimes it gives positive values, sometimes it gives negative values (low values), being which in principle should not give any values, because most of the time I am not consuming energy from the public grid, nor injecting it, because I am in off grid mode. Is it normal for this to happen? Thank you!