In the collections tab you can re-acquire shaders and it says to unlock it you have to dismantle an item with the shader. I had it applied to my exotic helm and since it was a low level/stat one from when leviathan first came out I dismantled it for the shader. However it didnt unlock the shader to re-acquire, it is the Leviathan prestige shader not sure if that matters. I still have it on my rocket launcher and I am thinking of trying it again but I wouldn't want to do it if I don't unlock the shader. Anyone experience this too or have an answer to what you need to do to unlock it.