Show us some odd ignitions from the past

I would not think so. But probes CAN go bad and you can blow them up.

The pulse is very narrow maybe it's "hidden" by a trigger delay and only displaying the residual wave. You can check the probe "redneck" of course first by the cal output on the scope. Then set it up for the highest range on DC and read the cap with the CD powered and engine off. You should be able to read the DC of the charged cap, just a straight line trace fro 0V, unconnected, to 300V, at the cap +. Double check the accuracy by simply reading the cap with your multimeter under same condition