Not sure if this is a bug or not, it could be an “off by one” bug,
Easiest to do this in “mm” mode
Create a rect, set depth to material thickness and fill. In “Shape”, set width to 200, height to 50.8, and set position top left to x=25.4 and y=200.
Create a rect, set depth to material thickness and fill. In “Shape”, set width to 200, height to 50.8, and set position bottom left to x=25.4 and y=200.
Thee should now be two identical rects full depth cut out, butted up to each other 3D view should show a complete cut out, 101.6mm by 200mm
Use the mouse to drag to select both rects, then select “combine” from “edit” menu. Now select “outline” for the cut, and there is a line cut between the two rects.
Now repeat, but for Rect #2, set the y=199. This time, the resulting combine doesn’t have the center line, which was my expectation for the first time.
Might even be “off by 2” ( or + instead of - etc), since if the top of Rect 1 is at 200mm and the bottom of rect 2 at 201, they are still butted up to each other, and combine should make them a unified lump.