I get the same problem as you. Even setting
Label1.Alignment = "TOP_RIGHT"
does not give the expected behavior
You can set the "Extra CSS" to
-fx-text-alignment: right;
to make it work
There are other labels on the screen where it looks like the right-set alignment is working
The expected behavior works for labels with 1 line of text.
For more than one line of text, I guess the inner block of text is aligned to the right of the label size, but the text is not aligned to the right. This text alignment has to be done in css.
Edit: (to clarify)
I imagine that the label is a bit like a hBox? There seems to be a Text node inside the label, and that Text node is aligned to the right or not. The label computes the width of the Text node, and align it within its boundaries. So in order to modify the alignment of the Text of the Text node, it has to be done via css.
That's what seems to be the only reason for this behavior