Sloppy frame when using -Bxafg

The frame is very sloppy when using this one liner:

$ gmt pscoast -RNO -JS0/90/20c -Gblue -Sgray -pdf test -Bxafg

I dont think it’s supposed to look that way.

Looks fine if you add a MAP_FRAME_TYPE=PLAIN or -Byafg.