Orion xs overvoltage

Has anyone had problems with the Orion xs outputting major overvoltage? When it idle ie engine not running it the output voltage rises to 16.5 volts and even if I turn it off it only drops to 15.5. Absorption is set at 14.2 and other settings less but keep getting this crazy output voltage which I know is correct as my battery bed is sensing it
Any suggestions welcome
Ps I am an electrical eng ( high voltage ironically) so know a bit about electrical systems lol

I think there was a problem with an older firmware version, you might try to update.