Right, I understand that it will get confused on some mixed impedance measurements where the meter is set to measure the minor component, but autorange is going into a loop when trying to measure a pure resistance below 200Ω or conductance above about 5mS. I'm not trying to measure the resistive component of an L or C.
I've tested it using standard low inductance carbon comp resistors as well as with a potentiometer (in order to fully characterize the issue), and it works fine until you get down to the hysteresis point of 180Ω. Below that, it down-ranges to the 200Ω scale, and suddenly displays a value far above the maximum for the selected range (somewhere around 1300-1500Ω), whereupon it senses over-range and up-ranges. Then, it's only measuring a couple of digits, so it down-ranges again and gets the bogus reading, ad infinitum. It never blanks the display at all, which is how I can see the numbers. Switching to the 200Ω manual scale works, of course, but shouldn't be necessary for a pure resistance.
Looking at the internal signals, something is generating a voltage spike when it down-ranges and the ADC is able to sample and display it before the voltage settles to the correct value. The voltage out of the unknown diff amp shows smooth steps, but somewhere in the variable gain stage before it gets fed to the ADC a huge transient gets superimposed on the measurement signal. I haven't tracked down the source of the extraneous signal yet. Again, this only happens with resistors below 200Ω; autoranging works fine with arbitrarily large resistors and all "pure" reactances. I haven't even seen it when measuring resistance of a primarily reactive component, though that may just be a fortunate choice of components. That's how I checked the D value for a couple of the large caps which I was having trouble with.