I found a piece of a print (very hidden) trapped along the rail preventing the Y-Axis end-stop from being triggered.

Appears to have been the issue.

I got an M2 for my son. Initial setup went well, using Simplify3D. He printed out several things from thingiverse with no issues. 15 to 20 prints no issues. Recently the unit started making a noise when the bed is starting a print. When the bed moved to the rear it appears that it is trying to move ...