I've observed an odd discrepancy lately between the data reported by the portal on the "live" card (i.e. the one at the top that shows current generation, consumption etc) and the energy graph. Having recorded the generation value daily for some time there is a definite difference between that and the generation figure reported in the energy graph card. As an example, the figures I have for the past two days were 27,2kwh and 24.7kwh, but the energy graph reports 18.8 and 21.42kwh respectively for those days.
When I look into the inverter log (Meter Data) for those days the "Generation Today" figure matches my observations (the larger figures), which leaves me wondering how GE are calculating the data for the energy graph.
The most likely cause is that on both days the inverter was offline for an extended period, so I'm guessing that the energy graph is summing the reported data by half hourly periods and thus missing data when the inverter was offline (and thus not reporting). The figures for reports look to be generated the same way.
Obviously this raises two questions. Firstly which is the correct data, and secondly what are the implications for other areas of the portal. I'm inclined to assume that the "Generation Today" figure in the inverter log is valid since it is probably calculated by the differential in Total Generation. Sadly both the energy graph and the new reports seem to ignore any figures for periods in which the inverter was offline, rendering the reports less than useful unless you can guarantee virtually 100% uptime.
I'll report this as a bug on the portal but if anyone has seen the same issue it'd be good to verify that my conclusions seem valid.