runout/concentricity issues with 1 CMM but not the others.

[[RP...]]

Recently we've had issues with one of our three Duramax CMMs reporting runout or concentricity 0.002 higher than the other two CMMs or concentricity gages.  All the CMMs share the same programs, calypso 2021, and same probes.  Measuring the sizes seems to be no issue.

CAD Presentation outputs the same visual, on either side of the cylinder.  Even after flipping the part.

What could be the main causes?

I've tried switching the fixtures.  rotating the part.  recleaning probes and the part.  each machine is qualified only once a week.  Any suggestions appreciated.

I have a step cyl from recalling circles 1 and 2 for spacial, nothing in planar, x and z origins are step cyl.  back plane is y origin.