Never noticed that before. A try with Gimp 2.10.38 and it is the same as with 3.2 The same effect using unified transform and the scale tools
If you use Layer -> Scale Layer , break the link between Width and Height then increase width that retains a sharp edge. At least it does here.
If you use Layer -> Scale Layer , break the link between Width and Height then increase width that retains a sharp edge. At least it does here.