I’m somewhat late to hear this news, but recently there was a bug in iMessage application of iOS and Mac platforms causing it to crash/freeze up as reported here.
The crashing character consists of 5 codepoints.
U+0C1C [Lo] TELUGU LETTER JA
U+0C4D [Mn] TELUGU SIGN VIRAMA
U+0C1E [Lo] TELUGU LETTER NYA
U+200C [Cf] ZERO WIDTH NON-JOINER
U+0C3E [Mn] TELUGU VOWEL SIGN AA
and has a complex ligature form.
Sadly the poor usage of Telugu language Unicode block is potential cause to discover the bug so late; however the root cause of bug is some unsightly buffer overflow in Apple’s codebase.
Who knows if Tamil Unicode has any equivalent horrible bugs living in Android/Apple/Mac/Linux/Windows platforms. Hopefully not.