At least in the industry I work at (making dubs), there is always a document called “As Recorded” that is an exact transcript of what was recorded, and usually doesn’t 100% correspond to the actual script.

I think the reason they do the subtitles like this is because they can’t be too hard to read. Some things just don’t fit in time, so they simplify them. I’m not 100% sure though, I could ask my mate that works in translating/subtitling.