Can a high current switching load damage a bench power supply?
Is it possible that voltage spikes (maybe capacitor bank is undersized

need to confirm this) at the ESC supply input damaged the sense lines and control circuitry in the bench supply over time?


Yes, it is possible. It would be safe to assume that the supply does not have input protection for overvoltage. It would be best to use diodes or some other form of input protection like this circuit:

Source: http://kaktuscircuits.blogspot.com/2014/07/reverse-polarity-and-overvoltage.html
A better way would be to monitor the voltage spikes with an oscillocope at the input of the supply to see what your up against. Very short spikes could be taken care of with extra capacitance, or minimizing cable inductance and a diode. Very long spikes might need something like the circuit above. At any rate, it's probably not good to present voltage conditions beyond the rating of the supply to it's inputs.