Indic Script Bug in Final Cut Pro X

A poster in the Apple Support Communities has pointed out that it's not possible to create Tamil language titles in Final Cut Pro X via copy/paste -- nothing happens. Direct typing also does not work right.

My tests indicate that the same copy/paste bug affects Burmese, Bengali, Kannada, Khmer, Oriya, and Sinhala. On the other hand, Devanagari, Gujarati, Gurmukhi, Lao, Malayalam, Telugu, Thai