Why does X3 Hybrid G4 report parallel fault in parallel mode even though the firmware version is the same and the master and slave settings are correct?

You can try to switch the master-slave position to determine whether it is caused by the communication failure of one unit, and you can also try to enable the system off function in the remote setting of the inverter, and then select system on after remotely shutting down the inverter to synchronize the synchronous output signals of the inverter as much as possible.