Focusing on the DC volts, and without regard to sign (+ or -), it is apparent that the measurements were at the lowest end of detection

0.00E+00 0
1.83E-05 1
3.66E-05 2
5.50E-05 3

The question is this: was the meter actually measuring something? (Did the probes come disconnected?) We do know there were long periods of zero activity in this system so this may have been during one of those “zero” periods.

That gives some background that might help.