The seam is present in both the Cura and s3d gcode…so I was thinking it might have something to do with the multi material start script, used in both slicers, so I tried editing out the multi material code so that only a G28 was left in the script but, no big surprise, the seam was still there. ¯\_(ツ)_/¯
Elevator Multi Material 3D Printer