Temperature control panel

Hello everyone. I bought a new kingham last year and this summer the temperature on the control panel has started showing minus on the outside when it's actually way above but plus on the inside and I'm getting text alerts for frost and water in the tanks. It's been back to the dealer but they can't find anything wrong. Has anyone else had this problem. 
TIA

I've not heard of such a problem. Just insist that the dealer corrects it, that I's their obligation