Friend just had his new to him  STS delivered,   and I notice that  the speed sensor on the  RHS of the shaft that crosses at the front of the feeder-house has the LED on it illuminated, even when combine is shut down  and key removed. This  shaft drives the chain that runs up the RHS side of the feeder-house and ultimately drives the feed elevator.

Is this just how they are, or is it a sign of electrical issues ?    Seems slightly odd to me.