By measuring the resistance of the ladder, I obtained a graph of resistance as a function of voltage.
All the heater elements behave consistently, showing only a small standard deviation.
However, heater element 5 shows a significantly larger standard deviation.
Upon examining the initial ladder graph, I noticed that the resistance of heater element 5 increases following a power outage that resets the system.
At this point, I am unsure why this behavior occurs.