I have seen this behavior on Sense 6 Roms including Viper and the ATT Debloated with integrated voicemail into messages.
The problem appears to involve Google TTS because whenever I go into setting/language & keyboard/text to speech I see that the system is stuck on "checking default"
Skydragon Sense 6 on the other hand works fine.
I've been trying to see what the difference is without coming up with a solution.
Have others seen this?