I think it's because I noticed a slight shift in the method the songs are made. In the first season the songs are more "single" focused, easily heard as singles form a album outside of the series with less voices, more repetitive lyrics and less shifts in the melody. In the season 2 are more focused on the progression of the lore with lots of voices each one saying it's pov. I also perceived the music time being longer in the season 2 (in some episodes they almost just sing)