Thanks for taking the time to review. The only reason I can think of for that behavior is if in the YouTube captions the video has "[ _ ]". That is a form of censoring that YouTube does when they automatically generate captions, and its kind of a fill when they come across several different "curse" words. APF is including "[ _ ]" automatically on YouTube, and right now there isn't a way to turn it off. If that is the issue though, I'm happy to add a way to disable that if you'd like.

UPDATE: The new option has been added (Options page > Audio tab > Mute pre-censored captions on YouTube)