i have 2 MPII with a 3.8kW Fronius inverter, they seem to work well, the only issue i have encountered is that I am not able to see the current or voltage, only power.
I have the same settings, I talked to a fronius rep, it looks like it is a new issue. At least here in México, the fronius team is yet to discover the workaround.
i think flashing the fronius primo back to an older version should work?