I don't speak spanish, but I did notice that. The subtitles start to get more "fag" in them in the back half of the season. And one of the episodes wasn't subtitled at all, I had to go in and turn them on. THE HORROR.
It's actually kind of strange and I figgured it was a quirk of the subtitles instead of any real change in what they were saying. Hermano, Hombre, Amigo also seemed to be kinda loose and interchangable.
And i've always heard that "Puta" means not "Motherfucker". But there's a pretty long scene with one of them yelling "..., Puta!" and it's translated as "..., Motherfucker!" So he's just callin them pussies I thought. What a weird thing that they cleaned up "You Pussy" to "You Motherfucker".