font rendering fails for Malayalam language after updating to Sierra

Language: Malayalam (Language spoken in the southern part of India); Language tag: ML

Problem: font rendering fails

Expectation: As per Unicode input standards, an input in the sequence [consonant + visarga + Malayalam character ra] should give the output [pre-base ra symbol + consonant].

In El Captain: Worked properly

In Sierra: Only some fonts works

Description: Fonts with legacy MLYM script tag of open type specifications work as expected. Fonts with new updated MLM2 script tag of open type specifications fails. Instead of forming the prebase symbol, it just displays chandrakkala (visarga) and Malayalam letter ra. At the same time, if this is at the beginning of a paragraph, it displays well in pages or libreoffice writer. But if it is inside a word or even if is the first letter in the second word, this does not work. In textEdit, it fails to form the prebase symbol even at the beginning of a paragraph.

Screenshot provided: (taken from pages) Font names are written in English. You could see that, the prebase symbol forms, while it is at the beginning of a paragraph. But the same sequence fails when it is the second letter in a word. Here, the sequence used are:

1. ka + visarga + ra + i symbol + ya => kriya
2. pa + visarga + ra + ka + visarga + ra + i symbol + ya => prakriya
3. sa + chillu R + ga + pa + visarga + ra + ka + visarga + ra + i symbol + ya => sargaprakriya

System Configuration: