No, that's not what they say. If you read the text that you just now quoted, you will see that it says "storing your 2FA in your password manager is an acceptable solution due to the convenience benefits it provides". Clearly the writer of that text believes there _is_ something wrong with having 2FA completely separate from the password vault: it is less convenient, to the extent where they are happy recommending this horrible approach to laypersons.

In addition, if you go and read OP, you will find that they talk about the potential of losing access to your TOTP codes stored in Google Authenticator. So that's another thing that counts as "something wrong" with storing 2FA separately from password vault.

So there's at least 2 things in the article that count as "something wrong". So they definitely didn't say that there's "absolutely nothing wrong".