-136 amps at 24 volts is a very large load. Bigger than a windlass. So as long as there is nothing like that running, then its an instrument problem.
What does it read with all loads shut off and battery charger off?
Do you know if the meter uses a shunt or a coil?
Trace the leads from the meter. Check for loose connections.
first turn off your inverter
Ammeter may actually be a voltmeter reading the voltage drop on a shunt (very low ohm resistor). If a poor connection on the shunt, the volt drop can swing wide even though the amps are normal. Trace meter leads and see if they go to a shunt.