
Ohm's Law for a diode, relates the current through the diode to the voltage across it, by an exponential relationship, the 0.7 volts is just an approximation, and it really depends on where on that curve you are.
With a reverse voltage then the current should be zero, but really it is just a minimal value so the circuit should be "off"
The next question is how and when do you reverse bias that diode in the circuit, at what point in the pulse train? It is reverse biased when the voltage on the secondary is lower than the voltage on the choke at the end that connects to the diode.
But since voltage is relative it becomes more unclear, you have to choose a reference for the circuit, which may or may not be grounded on the secondary side.
I think a differential probe across the diode would be a useful step.