Collection and :name permalinks - unicode tamil


I was trying to generate several pages in tamil language under the collections feature of jekyll. Feature works as expected but permalinks seem to be the an issue.

Problem is when i name the files in tamil unicode, there seems to be an issue while generating the same as html name in permalink - aka - filenameoutput.html.(one or more characters )
(eg) collection:
The expected output under collections :name permalink is
However what was encountered on build is
அகக-களி.html i.e

so basically character is messed with - while rendering into html.

Note: Concerned website - Thirukkural
Also tested on local ubuntu machine.
When generated under posts as permalink, works as expected.
Issue is with collections and permalinks; and definitely not the content.
also does it qualify to be bug ?

Thanks in advance