High voltage on panel above the sink

[Viperdogg]

My panel reads 18 volts. This is true when plugged into shore power or not, converter breaker switch on or off, and no solar panels. At the batteries, my multi-tester says 12.5 volts on both batteries (I just replaced them today) with shore power connected and the converter breaker switch on. Battery cables and batteries are not warm.
Has anyone else experienced an erroneous readings on their panel? I know the water level and gray/black levels can be erroneous.
If its not the panel then the converter may be may faulty?

Thanks in advance for any tips.

[OTRA15]

Your other thread FEI:
https://www.airforums.com/forums/f44...ng-219443.html