Resolved Lohit Oriya rendering issues with Harfbuzz NG
Cross checking with Windows found those are breaking with Uniscribe as well.
One of that combination was 123 Gsub listed at UTTRS
ର୍ତ୍ତ (U+0B30 U+0B4D U+0B24 U+0B4D U+0B24)
Reph was not allowing to form expected ligature
Same way there are some other combination like 52 ( ଞ୍ଜ)
If someone type ି or ୈ, It was not allowing to form expected ligature.
Fixed these combinations in upstream now. 
Build lohit-oriya-fonts-2.5.3-3.fc18 will be available in tomorrow update-testing repo. 
Fedora language testing day is planned on 2013-05-02 
If none more issues get reported during this test day, i will do next release of lohit-oriya that is 2.5.4.