I came up with this question when I received an email from a committee with a sentence 'We have decided not to publish it', which seems really strange to me because the grammar I learned in English classes is 'decide not to do something' and 'decide to not do' was told incorrect.
I searched for answers to this problem online, but did not find a clear as well as persuasive answer. In terms of grammar, is 'decide not to do' correct ? If it is incorrect, is there a reason why people say 'decide not to do' even in official letters ?