Talk:Riven Mods/@comment-178.77.36.8-20170723184840/@comment-76.182.242.161-20170729052448

the 25% seems to be the sum of all possible riven drops on the sortie page:

Rifle Riven ModRare (6.79%)

Pistol Riven ModRare (7.61%)

Shotgun Riven ModUltra Rare (1.36%)

Melee Riven ModRare (9.14%)

just bad luck I'd guess.