Fired up the pentair heater today, would not start. I notice on my aqualogic panel the spa temp was 75, which is realistic...but the RED digital temp display on the heater says 108 degrees, clearly wrong and probably some sort of safety mechanism shuts heater off if too hot?

So, someone told me that maybe the water sensor (the black 1" long peg that is stuck into the plumbing) may be bad....but if my water temp is reading right on aqualogic panel, cant be the case?

Why does heater show 108-106 when it is NOT that hot?
any ideas?
Thanks