That was a very honest and accurate response from Minelab.
I agree with an earlier poster, greatly increasing the VDI scale to more than double compared to the older X-Terras, and the Equinox 600/800 has caused some major target ID jumpiness. If your soil/sand has even a little magnetite that jumpiness, instability and severe up averaging of low and mid conductor non ferrous targets will be even worse due to the XT Pro being selectable single frequency only and not simultaneous multi frequency. However, the Equinox 700, 900 and the Manticore by no means have stable target IDs on deeper non ferrous targets and they have a very similar expanded target ID scale like the XT Pro. Running those SMF detectors using their single frequency option results in very similar behavior to what you are describing.