If you reposition the Origin using the “reposition Origin” tool the origin is re positioned and the displayed XY cords relate to the new origin. Ok no issue on that.
The issue I see is that when you select Properties of that line the XY Coords relate to the Sketch or Sheet origin the main “WCS” value not the UCS.
There is enough room in the Properties Dialogue window to provide for both WCS and UCS values. The underlying values are already in memory/derivable simply so why not display both in the Properties Dialogue. Seriously it is not a programming complex matter what ever a programmer has to say.
Why have a property you wish to check with the origin referred to is not the one you are at that point working on.
There are times that I consider that program design is driven by programmers and not aimed at the LCD aspect in design. That is a general statement not specifically aimed here.