Not sure what is happening here. I've set INSET 1 for both the center left-right stretchers in the attached cabinet (jpg also attached) at 13.25". However, when you view it, they are not at the same position. Take cabinet into faceframe editor and you can see the difference their position.
This is happening in two different cabinets.
Is this a display issue or a positioning issue? Yes, video drivers are up to date with manufacturers (not Windows) drivers.
In your attached picture, on the left stretcher, Inset 1 is referencing the top of the partition. The right stretcher Inset 1 is referencing the top of the end panel. The partition is under the top where as the end is above it. You'll need a numerical difference in them to achieve the same dimensions. If you don't feel like doing the math and want to make it like the other, you can delete the stretcher and add back in choosing the side first, then the partition. Or you can use the installed stretcher, go to the advanced tab, and set Inset 1 to reference the top of the right end.