This is a relatively common malfunction for the installed firmware in some old electrical devices to become corrupted. I often see this in repair videos, and there's often an easy fix - reflash the firmware using any available method or directly with a programmer. I even encountered this myself when my router failed out of the blue, after which it was repaired using the above method.
What about a preventative firmware reflash? Could, for example, reflashing the same firmware version five years after the last vendor's update reduce the chance of data corruption? If, for example, there is a constant chance of the appearance of corrupted bits, it would be reasonable, right? Or, on the contrary, could it carry some hardware risks for an old equipment (besides the standard risks of any reflashing)?