Fronius binding: Positive values for PV_Load_Power - how?

I recently setup OpenHab2 to include my Fronius Symo 7.0-3-M with a Smart Meter 63A.
According to my understanding, the value PV_Load_Power should represent the amount
of power currently drawn by my house.

So in my understanding I expect this value to always be negative, representing the amount of power drawn by the house. The value is negative for like 99,9% of the time, but sometimes I receive values like

2020-05-04 16:40:42.435 [vent.ItemStateChangedEvent] - PV_Load_Power changed from -237.3499999999999 to -145.1099999999999
2020-05-04 16:40:53.858 [vent.ItemStateChangedEvent] - PV_Load_Power changed from -145.1099999999999 to 342.5799999999999

where the amount suddenly goes positive! How is this possible? Wouldn’t this mean that my
house is emitting power to the network?