Myanmar/Burmese font not rendering correctly

[mapmeld]

Hey on the MapTiler site I noticed that Myanmar/Burmese labels are not rendering correctly. It is always tricky script to get right with harfbuzz, and WebGL doesn't make it any easier. Let me know if this is the right repo to file an issue.

One example of the problem is in the name of Myanmar - the first character (မ) is followed by its vowel sign ( ြ ) and they should combine into this: မြ but on the map tiles, you see the bracket-looking vowel mark around the next letter. Each character is added individually without regard to these combinations.

A related issue appears in some Bangla/Bengali labels in Bangladesh, for example Chattogram/Chittagong. The character ् should join two consonant characters, but instead it appears as a mark below the word and the surrounding characters are unmodified