@brent113. I will perform both of your suggested checks. Interesting that you did the Z-axis alignment from the Y-axis drives versus the bed. Thanks for the information!!
Question, have you observed non-unison movement of the Z-axis drives? I observe it at times during a Home operation. I may not be recalling correctly, but I think it may occur on upward motion, as if one z-axis drive continues to move after the other stops.