Mariln firmware issue

I have been building a RAMP 1.6 system using Marlin 1.1.x-bugfix (which is 1.1.9 I believe) in an old 3D printer that had it's proprietary control board blow. For a while I've been trying to get it to print a 100mm cube without an odd layer 10-15 issue and then clears up to no avail so it's been sitting. I assumed it was mechanical and never got back into fixing it.

I've recently decided to try to print some face mask ear reliefs for our local hospitals, but the layer issue has turned into an offset issue. Regardless of the settings, layers 1-5 print near flawlessly but 6-10 are offset exactly 12mm [attachment 115263 20200413_125907.jpg]. I would assume if it was a mechanical issue, it would vary on the layers affected, position on the bed, orientation, print speed etc.

I've looked at the gcode file with OctoPrint, Slic3r and Cura (which generated it) and none show the layer offset so I'm suspecting it's firmware, but WHY is the question. I saw a bug report on it in the Marlin bug tracker, but it was closed with no defined resolution that I could make out. I'm suspecting it's something specific with the DRV8825 drivers since some have the issue and other do not.

I'm running another test print with the pattern turned 90deg to see if the offset follows the axis or follow the pattern and changes to the X axis.

Any help would be greatly appreciated.