Depends entirely on the details of your 12V system, but quite likely yes, IMHO.
Most 12V/car devices don't like to see much over 15V, so if for some reason your controller or battery failed to hold it down (and it might have an open circuit voltage of up to 40V), then *pooof* out comes the magic smoke.
On the other hand, if you have a smallish 24V panel charging a big 12V battery via a robust but non-MPPT controller you'll just be throwing away more than half the available energy since PV behaves as a constant current source under heavy load.
Rgds
Damon