It may be because October 7 is First Friday this year.
I don't think First Friday has anything to do with it. Earlier this year, May 8th was the External Solemnity of the Ascension; May 29th was the External Solemnity of Corpus Christi; and July 3rd was the External Solemnity of Ss. Peter and Paul - the feasts of the Ascension and Corpus Christi being on Thursday and Ss. Peter and Paul on Wednesday.
I have pinged jrny who is more knowledgable on this sort of thing than I am.