بسم الله الرحمن الرحيم
Followers of Ahmad al-Hassan claim, that the book of Sheikh al-Saduq (ra) contains the statement "from Yemen" only inside the brackets. The truth is, that there are two different hadith in the book "Kamal al-din wa-tamam al-ni 'mah" which mention "Yamani" and only one of the narrations contain "from Yemen" inside the brackets, the other one is clear.
So, If we refer to the book, we will see, that the hadith # 7 contains [from Yemen] inside the brackets. And in the hadith # 16 "Yamani from Yemen" has been mentioned clearly.
 Kamal al-Deen by Sheikh al-Saduq, Volume 1, page 307, Hadith # 7
 Kamal al-Deen by Sheikh al-Saduq, Volume 1, page 310, Hadith # 16
(Click on the image below - in order to enlarge ;)
 - (Hadith # 7)
 - (Hadith # 16)