MPPTs can limit the input current from the solar panels with the intent to maximize power production.
For example: the PSW-H 5KW-120/48V model’s max. usable current is 18 Adc per input, because there are two independent MPPT inputs on this model, each one can use up to 18 Adc of current from the solar panels.
What this means is that if you have a solar array that has an MPP current larger than 18 Adc, the MPPT will limit the input current to 18 Adc and consequently operate closer to the Voc, straying away from the Voltage Maximum Power Point (Vmp). This would mean your voltage input/output ratio would be larger, thus indicating larger losses (via heat) and less power output.
One must be mindful to never surpass the max PV voltage of the corresponding unit as this is a hardware limitation and will damage your inverter (for the PSW-H 5KW-120/48V = 250 Vdc). Please refer to chapter 5.6 PV connection to find out what maximum current & voltage is listed for your Any-Grid PSW-H model.