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

An episode of The Simpsons where Homer was driving with a bucket on his head said ‘stupid car’ but the CC said stupid Ford.