In your case, I wonder if they haven't built in a high megohm resistance between their Neutral and case ground. Or some TVS leakage or capacitive coupling between Neutral and Ground.
I was thinking something similar, that a Filter was responsible for the readings; however it could simply be Capacitive Coupling, as the OP has indicated the Analog Meter's Pointer indicated 0 Volts on the L-G tests, yet the DMM measured E on both L-G tests.
Even though both Meters exhibit a High Input Impedance, the Analog Meter might be 100K Ohm, and the DMM might be 50M Ohm - much higher Z than the Analog Meter.
--Scott (EE)
