I am in SolidWorks 2025 SP0. I have never seen this in SolidWorks or any other CAD package. When I add a Smart Dimension in the parent view (drawing scale of 1:5), then do the shift and drag to put it on the detail view (scale 1:2), the value is correct (3.18 [0.125]). When I create a Smart Dimension to the exact same lines in the detail view, the value shows as 4.49 [0.177], which is incorrect. Did