Reported by user in this thread: https://forum.duet3d.com/topic/38718/strange-behaviour-with-mesh-bed/
Setup:
Voron tap probe (M558 P8 unfiltered switch) connected to 6HC mainboard
Z axis mapped to 2x 1XD expansion with external drivers
User reports accumulation error of Z probe readings in RRF 3.6.1 and 3.5 (exact version not specified). In 3.4.5 there is no probe error accumulation.
Moving the probe to the 1XD appears to resolve the issue, but underlying issue of a regression in motor reversion with this setup remains.