If they’ve been dead for a while then the body is going to be quite decayed so that unfortunate person would end up dying again immediately.
Unless you’re suggesting this thing that came to life is no longer human. So in that case decayed body/flesh, missing organs/bodyparts, etc. no longer prevent it from “life”. But I’d argue that isn’t a human coming back to life, more like a corpse transforming into something else.
To be fair your post title does not match their own text
So it’s not all accounts, just the ones that don’t already have 2FA. Personally I wouldn’t have noticed any changes since I already use 2FA enabled with an authenticator app. But I can see how this might bite you in the ass if you weren’t already using 2FA.
Interestingly I used to run into a similar issue when using Lastpass. When logging in from other IP addresses they would often do mandatory email 2FA, and of course I couldn’t get into the email account without Lastpass. But it sort of resolved itself since I also have email on my phone so I just had to make sure those Lastpass emails didn’t end up in spam or wherever.