Trailer Solar Setup

We recently got a new trailer and the other day we got a warning on the charge controller saying Over voltage. I checked the app and it was showing a battery voltage of 22.6v and a PV voltage of around 12. I removed the battery and checked the voltage with a multimeter. The battery showed ~12v so I checked the app again. I noticed the PV voltage had gone down to .453v. So I checked the wires that go to the battery with the multimeter and got the same reading.

So my question is where is the 22v coming from??

I have a Go power 30 amp GP-SB-PWM-30-BT controller

I also covered up the solar panel a bit and the voltage went from 22.6 to 20. Is that normal?