[NTG-context] Proper ligatures in Malayalam

Hi, I tried to make a document in Malayalam, an Indian language. However, the ligatures don't form as expected. A minimal example is \mainlanguage[ml] \definefontfamily [malayalam] [ss] [Rachana] [features=malayalam-one] \definefontfeature[default] [mode=node,kern=yes, liga=yes,tlig=yes, ccmp=yes,language=dflt, protrusion=quality, expansion=quality] \setupbodyfont [malayalam] \starttext അദ്ധ്യായം \stoptext What setting am I missing? The expected form is show in libre office with the same text and font, attached as an image The sequence of Malayalam characters used is U+0D05 U+0D26 U+0D4D U+0D27 U+0D4DU+0D2F U+0D3E U+0D2F U+0D02 Thanks, ajith