Words that start with S don't live lipsync

Ever since the lastest update, I've noticed that my puppet's mouth no longer syncs with words that begin with S. So if I say something like "shucks" there is no puppet mouth movement. I've checked the rigging and it correct and if the S in not the first letter of the word, it will pick it up. Mic is real good and I boost the audio. Has anyone else experienced this?