Why are captions on TV shows sometimes different from the words the actors say, but in ways that aren’t explainable by being misheard by a transcriber?

Question

For example, the actor in the movie just said “I’ve been saying that”, and the caption said “I’ve said that”. Do the transcribers have access to the screenplay, and use that as a starting point?

In: Other

Answer 1

I believe some captioning/subtitling is done based on a copy of the script, but in actual performance the actors may change a few words. I’ve also seen some where whole responses, whole lines, are omitted in the audio, but the captioning is still there.