i think this has something to do with a special feature in the agilent.
the agilent machine can actually measure ohms while a voltage is present !
Here is an example : you have a ground wire coming from a machine. Let's say there isa problem with this ground wire ( loos / bad connection ) and the resistance is around 40 ohms.. Due to leakage in the machine there will be a voltage present across this wire.
Attempt to measure the 'resistance' and it is possible that the meter says : very low. simply because the measurement is upset due to the voltage drop across the cable.
The agilent meter WILL give a correct reading . That particular model that dave has has this special feature built in. (Qik-V and Smart-Ohms)
The way it works is that they switch the ohms current source off and sample the incoming voltage, store it in a cap and then pull off sime trickery ..
by 'force-feeeding' 220 into the meter in ohms mode i suspect that there is so much residual charge in this sampler that it simply takes a long time to bleed off.
I suggest the following test :
switch the meter out of auto range and into the 400 ohms range. activate the dual display ( so the temperature goes away and a voltmeter or ampere meter appears ). now do the test again...
This is a measurement technology not present in any other manufacturer.