I level my z-axis by manually adjusting screw rods to get the height of the right side to match the left side as I measure from the motor deck to the base of the z-axis housing on each side. Over a few hours of operation the two sides do not track together, and are 4+ mm out of sync. I either re-sync the left and right screws, or keep adjusting the bed to compensate.
I’ve ordered the auto leveler, but not sure if this will compensate.
Any suggestions?
It is possible that your lead screw nuts (or some other part of the Z axis) is binding at part of the movement. Check you have the spindles only 5mm inserted in the flexible couplers, and try loosening and tightening the fixing for the nuts. See this for more details. prusa i3 - Z-axis steppers and bed alignment problems - 3D Printing Stack Exchange
