I thought about something similar today. My kid (2.5 years) watches some stuff on Netflix which is translated to Swedish from English. It's very obvious that the voice over and subtitles are done by different teams/companies, because they often mismatch. What I find more interesting is how they differ, and it's related to the "slang vs academic" but it's about culture and context. Stuff like word puns that doesn't work when translated directly, or named being "translated" in one but used directly in the other. Honestly I think it's extremely lazy and cheap on Netflix' part, for adults it's one thing, but for kids it's pretty confusing. (My son is not reading the subtitles yet though)

I've always noticed this (even before Netflix) and I always assumed that it's because the dub is meant to somewhat match the character's mouth movements, whereas the subtitles don't have such restriction. So I always assume that the subtitles have the more accurate translation compared to the dub.

I was watching a German show on Amazon Prime with both German audio and subtitles. I was confused as to why on practically every line, the wording had been changed despite the meaning being similar.

I eventually figured out that the German subtitles had been machine-translated from the English subtitles!