You are correct and it was a challenge for me initially to find Spanish subs that matched the Spanish audio. But I eventually found like 7 really good dubbed series that had a perfect match. Once you're more advanced you can start with original series from the target language. I didn't do much of that.. instead I watched a ton of series from Spain and Mexico without subs.right. And this makes learning Spanish hard as opposed to learning English.
Almost all movies with English speech have matching English subtitles.
Not so for Spanish. Spanish subtitles are oftentimes independent translations of English subtitles. Do not match Spanish speech.