Yes, it depends on the team. There are some teams which strive for perfections and others that leave things as they are.
For instance, have you seen "Jewel in the Palace"? Which, by the way, is one of the best sageuk dramas ever made (or, should I say, "best dramas")?
The work which was done on "Jackpot", I remember because I was Greek mod there but I read all the Team Discussion to enlighten myself on historical stuff... They were searching and discussing every little detail, going to learned friends and professors if something weren't to be found etc.
And even in non-historicals. I happened to ask the Greek moderation in Misaeng: Incomplete Life many years after it had finished airing. As I was editing the Greek, I happened to see some English typos and other stuff. I made a list and when I was finished I wrote cgwm808 who was the English editor, asking her: "May I send these to you?" She readily accepted and went back to make all necessary changes, although it was a project long finished and "archived".
Now, on Where Stars Land (full of technical/aeronautical terms and incomprehensible OST), I had the honour of being part of the English editing team, and I'm proud to say that if on episode 30 we found some term was better said in a certain way, we went back to make corrections to episode 1!
The same happened on About Time. After an episode was edited and released, Channel Manager Piranna went through it and noted down anything we had forgotten, even spaces or commas, and bugged us until we had corrected it.
On the other hand, there are some mods who don't even care to reply if you write to them about an obvious error, let alone go back and change it. And of course this is true not only for English but for Other Languages as well.
That's why I'm saying, standards are different depending on the team leaders and their willingness to strive for excellence.