[HarfBuzz] strange rendering of some hangul jamo sequence

[Dohyun Kim]

Hi,

With the font downloaded from
http://ftp.ktug.or.kr/KTUG/hcr-lvt/HANBatang-LVT.ttf (file size is huge. sorry),
all the hangul jamo sequences are rendered quite well, except only one case.
The only problem is the sequence of U+1112 U+119E U+11AB ("ᄒᆞᆫ"):

$ ./hb-view --features=+ljmo,+vjmo,+tjmo,-ccmp,-calt,-rlig,-liga,-kern
./HANBatang-LVT.ttf "ᄒᆞᆫ" | display -

displays nothing!  I tried to debug by using -DHB_DEBUG=100,
but could not find what is wrong.  It seems, and I hope, that the font
has no problem.

I am quite curious about why only this character sequence is rendered wrong,
while all other cases are OK.

Regards,
-- 
Dohyun Kim
College of Law, Dongguk University
Seoul, Republic of Korea