Weird Z Axis Issue

Hi guys. I'm having a weird Z axis issue. It seems like for the same number of steps, the Z axis will move more in the upward direction than it will in the downward direction.

In essence, if it moves 10 steps up, then 10 steps down, it will be higher than where it started. This is causing the nozzle to be too far from the bed in certain places, even after performing the Marlin bed leveling routine.

Any idea how to fix?