It’s because the “primary” genset mode is Power Management, because of option G5. Then you are also able to run “another” genset mode, etc. “Island mode” then the units will be operated as island, but by the power management (G5 option), BUT only when the units are in AUTO-mode they will be a part of the total PM system.
NOTE: the genset mode, can ONLY be selected from the mains units. Then it will be transferred to the other units by the Can-bus automatically.