Z Probe/Auto Bed Level Issue


I’ve been pulling my hair out for days. Using a Wilson II with standard hardware, upgraded to an inductive probe. The probe works perfectly for normal homing, passes the Marlin probe repeatability to within 0.1mm across the bed. The bed is pretty level to begin with. However, whenever I run auto bed leveling, the Z “0” changes on the order of a few millimeters! After running G28 again, the Z offset is perfect again.

Has anyone else worked through this issue before? I can copy/paste tests from marlin (verbose leveling debug, etc) but I don’t know what’s relevant and what’s not.