I had an Arsenic Bite-4B with Glacial Whisper on it. I masterworked the weapon because it had a good roll, but then I saw that I didn't have the shader in my collection and decided to dismantle the weapon, however that didn't unlock the shader for me, instead only dropping enhancement cores.
Please fix this bug, thanks!
-
Not a bug, year 2 rare shaders aren't guaranteed drops from dismantling.