Exported font doesn't compose decomposed correctly using anchors

I am trying to test my braille opentype code but the symbols seems to export in the wrong way. The dots are set side by side instead of being composed vertically as is scripted in ccmp through anchors in the glyphs. Test glyphs that contain the same components work fine inside Glyphs.

Here is “⠳” in my exported font.


It is supposed to look like this.


Edit: I forgot to change the marks to Mark and Nonspacing. That fixed it.