Incorrect closed captions in movies.

[jimbofish]

It's my understanding that closed captioning in movies are prepared ahead, then timed and inserted into the signal so they appear in sync with the dialog. One would think that whoever is doing this would have the time and opportunity to make sure the captions are accurate.

I watch a lot of old movies on TCM. I've begun to notice that there are frequently words missed or substituted. The meaning is the same but the actual printed word or phrase is slightly changed. Not a big deal.

Recently I watched the classic movie "12 Angry Men". There are several references to the defendant 'getting the chair' if found guilty. The caption however, says 'lethal injection' instead. This isn't the same as the minor phrasing variations elsewhere, but more of a deliberate substitution. I can't think of any reason why they would choose to use that term as it just doesn't seem to fit the tone of the script. The actual audio still says 'the chair' so why just change the caption? I've watched this movie many times and don't remember whether it's always been that way or if it was recently changed.

Anyone else notice this and maybe have an explanation as to what's going on?