Ran into this as well, z-tilt adjustments getting worse with each iteration, I don’t recall fix though. However…
History for my printer.cfg edits mentions …
Which included config change to reverse direction for at least one of the steppers…
Consider checking out that change and others made around the same time. Hope that helps. Cheers!
Edit: Separate from this issue, I found my overall bed level variance was better if I did 4 point tests instead of 3.