With the DP832 on but all channels off:
I see ~7.5VAC@60Hz between channel1+ and mains earth. The other channels show 7.5-8.5VAC. The current is .022uA according to my 34465a, >20Hz filter mode.
So voltage, but almost nil current. Much ado about nothing?
With such measurements, I agree with you. No need to worry about.
In case of my DP832, I confirmed the measurements with 3 other DMM + my oscilloscope. All show voltage above 30 Volts.
All measurements where made with an input impedance of 10 MOhms. I think that in your case (44465A), and for the Keithley, the AC input impedance is 1MOhms. But that does not explains the big difference between my DP832 and Jason's one.
I also measured the current with 4 DMM. All show over 30µA, which is much much higher than your value, and not negligible. I am not saying that it is a dramatic situation, but just wondering in which case(s) I should take that in account.
So, it seems that we are observing DP832 with different characteristics.
For information, my DP832 shows a calibration certificate dated September 2014.
Could you try to measure the capacitance between earth and output terminals, and return the values?
It is more than midnight here, and we are switching from winter time to summer time this night. So, time to sleep
I will continue my investigations tomorrow.
P.S.: English is not my native language. Do not hesitate to ask for clarification if needed.