I'm not referring to the usual mangling of spelling or sentences, but things like referring to dialogue, music, or sound effects that don't exist, "jazz" or "rock" that isn't, or just plain wrong uses of words like "scoff" to describe what a character did.

i think it's sourced to a third party and they have to do them real fast sometimes. what the fuck do they care what music is playing? i think anyway...

What I've read is that the captions are often started while the episode is still in production and they work off earlier drafts of the script. If the director and editor have to change an episode last minute, then the changes don't get caught in tim

Maybe you can't hear the music or sound effects.

So far as I know I'm not losing my hearing.

Yeah, it's kinda interesting to see the changes. I was watching an episode of Fringe (I think) and the captions said an injured man was "at Mount Sinai", but the actual dialog was a generic hospital name like St. Mary's or St. Elizabeth's, or something. You often see instances where brand names are mentioned in the captions but generic terms are actually spoken (i.e. "iPod" vs. "music player"). I guess product placement deals fell through, or it couldn't get cleared by legal, or something?