DIAGNOSIS Yes, it's normal at no-load or very light load. The voltage regulator is designed to maintain ~120V under a 50%+ load.
FIX Verify voltage under proper load.
1. Plug in a load of at least 1000 watts (like a heater).
2. Let the generator run for a minute to stabilize.
3. Measure the voltage at an outlet again. It should now read between 115V and 125V.
4. If it's still above 130V under significant load, then the inverter board's voltage regulation may be faulty.
IF THAT DIDN'T WORK If high voltage persists under load, a failing AVR (Automatic Voltage Regulator) component on the inverter board is likely. The board needs replacement.
HEADS UP Modern electronics (phones, laptops) are powered by their own internal converters and are generally safe from this high no-load voltage. It's the sustained high voltage under load that damages motors and appliances.