Missing ligature for Old Burmese

[dscorbett]

Font

NotoSerifMyanmar-Regular.ttf

Where the font came from, and when

Site: https://noto-website-2.storage.googleapis.com/pkgs/NotoSerifMyanmar-unhinted.zip
Date: 2018-04-20

Font version

Version 2.001;GOOG;noto-source:20171016:bf6466d78425

Issue

According to UTN notofonts/noto-fonts#11, Old Burmese has a special ligature for ṣḍa. Noto Sans Myanmar supports it, but Noto Serif Myanmar doesn’t.

Character data

ၑ္ဍ
U+1051 MYANMAR LETTER SSA
U+1039 MYANMAR SIGN VIRAMA
U+100D MYANMAR LETTER DDA

Screenshot

[ohbendy]

This is even more confusing than I thought, fonts are behaving differently. The sequence I'm typing here is
ၐ္ဋ ၐ္ဌ ၐ္ဍ ၐ္ဎ
ၑ္ဋ ၑ္ဌ ၑ္ဍ ၑ္ဎ

Padauk gives:

Pyidaungsu gives:

Tharlon gives:

Myanmar3 gives:

Myanmar Text gives: