GPOS LookupType 1 at start/end of line when previewing text

When I configure LSB/RSB/TSB/BSB anchors like the screenshot below, the positioning at the start/end of a line does not change:

The exported font works perfect, and the spacing at the start of a line gets narrower, thus it’s a bit confusing especially when I switch back and forth between Glyphs and the other apps like TextEdit or InDesign. I can live with it, but I hope it gets fixed some time. Tested on both Glyphs 2 and 3.