This is difficult to explain so I will try to attach a video of what I am describing. Using offset in a sketch with radii works normal if the offset is in the original sketch. Offsetting from projected geometry does not maintain the offset if the original geometry size is increased by more than the offset. This has caused numerous problems throughout some of my models.
Another similar issue...start with a square extrusion, project outline, then offset. Add radius to corners, and fusion automatically adds dimensions to each side. Change the original geometry size and some dimensions will change instead of the geometry. If I delete the automatically added dimensions and add my own, it will act as expected.
Fusion
