If you have the Duracell system:
Someone may have reversed the CT clamp. This has been known to happen where another electrician has come round e.g. to install a smart meter and they have reversed the CT clamps.
At very low values of home energy consumption the load may be periodically slightly negative. This is a result of the system having different measurement devices. The load is not directly measured. It is computed as the leftover from the instantaneous values of PV, Grid and Battery power.
The PV and grid are measured by CT clamp.
The battery power is measured by an accurate meter.
These measurement devices have different accuracies at low power and can occasionally disagree by a few watts. This may manifest itself as slightly negative load.
Do you have a voltage optimiser installed as part of your PV installation?
This can cause issues with the current clamp power measurements if the inverter is on a different line voltage to that measured by the CT clamps .
For technical support for your battery contact firstname.lastname@example.org