pdladds Your system might need recalibrating.
Your battery (capacity of 8.19 kWh) was at 4% SOC.
So in 6 off-peak hours, you needed 7.86 kWh top up to get you to 100%.
That means 7.86/6 = 1.3kW rate to achieve your state of charge, with some margins here and there, results in roughly 55% of your current max charge rate of 2.6.
If your SOC goes from 4% to 100% in 90 mins, your effective kW charge rate would be 5.24, which isn't accurate for your spec inverter, so I would suggest to get in touch with Giv.
I wouldn't be surprised if you see some crazy quick drops in SOC percentage too....