Looks like this is already fixed in the latest version of fontmake (release 1.5.1, commit 90b0534620d74180f63501d0c8a03a190ce493f8).
Looks like this is already fixed in the latest version of fontmake (release 1.5.1, commit 90b0534620d74180f63501d0c8a03a190ce493f8).