If the EMS is showing 50 amps in when plugged into a 30 amp RV outlet... Then the EMS is defective and needs service.
It works by measuring the voltage between L-1 and L-2, if it's zero, you are on 30 amps (or less) if it's 240 volts (Well over 200) you are on 50 amps.
IT MAY BE (I have not read the owner's manual for yours) that someone hit an override and locked it in 50 amp mose.. You will need to download the manual if you do not have a paper copy and see if that is possible.. It is possible a full reset will fix it.
Try this: Unplug, do not start generator, Activate the battery disconnect and then lift the ground wire off the battery(ies) and then take a brake, say 1 cup of coffee.
The re-attach the ground cable, Re-connect the battery, and plug back in and see what happens.
No guarantee..... but this advice will cost you ... 1 cup of coffee.
Home is where I park it!