In our experience, the Solis and Samil ranges of inverters operate in a different manner to other inverters on the market.
During the evening when the unit stops actively providing a positive generation output, it goes dormant. However, it then draws a high current (approximately 2 Amps as seen in the output statistics) with a very low voltage by adjusting the inverter's power factor.
Clamp based monitors (all of our units being these) monitor current only - and so this will result in an artificially high reading in this dormant period; producing erroneous readings throughout the non generating evening period.
Unfortunately we are unable to absolutely overcome or mask the unique characteristics of these inverter models, and as such these will produce readings during the night with a higher generation value than that actually being generated within the property.
As noted earlier, all clamp-based monitoring systems will suffer from this issue - not only our own; therefore the only absolute solutions we are aware of would be either the installation of a wired-in solution (which often carries a hefty installation expense) or a pulse-counter system.