Thread:User talk:CodeCat/Syriac diacritics

I added a combining diaeresis filter to "arc" and "syc", but it does not seem to work: should produce a link to ܐܪܡܝܐ. The other diacritics I added work fine. Do you know what is wrong? Does the combining diaeresis somehow have a special meaning in a square bracket block in Lua regular expressions?