Aberant spacing of vowel matras and anusvara

Looking through my table of letter combinations using NotoSansGunjalaGondi-VariableFont_wght.ttf downloaded from fonts.google.com, I have noticed an issue with non-spacing vowel matras and the anusvara only in the Medium and Semi-Bold weights.

Specifically, the non-spacing marks (Unicode General Category:Mn) Ē and Ai vowel matras and Anusvara U+11D90, U+11D91 and U+11D95, as well as the spacing combining marks (Unicode General Category:Mc) Ō and Au matras, U+11D93 and U+11D94, which appears to be composed in the font as <Consonant> + Ā matra + Ē/Ai, do not align properly with nearly every base consonant - the only exceptions being Cha (U+11D7C) and Ja (U+11D80). In all others, they are misplaced horizontally, sometimes by a large distance, while others are lowered slightly such that they visually merge with the headline.

In contrast, using the regular (unmarked) weight, the non-spacing marks are positioned to attach / float directly where the consonant or long Ā mark attaches to the headline from below, as expected.

A note that might point to the source of the problem is that when the font size is changed, the amount of offset actually remains constant, such that for the most egregious misplacements, a 10 point vowel mark may be offset by as much as three characters, while at 96 point it will barely fall to the right of the headline. The offset also seems to scale proportionately by weight, such that the Medium weight offset will be about half as far as the Semi-Bold weight offset.

I observed this behavior in OpenOffice Calc and OpenOffice Write under Apache OpenOffice 4.1.15.

notofonts / gunjala-gondi

Aberant spacing of vowel matras and anusvara #6