I have the same issue too. Finished Exotic Quest on my Titan, then attempted to get it for my Warlock. Got the exotic pattern dropped from Wellspring, unlocked the Triumph that I unlocked the pattern. Went to the Enclave to craft it just for it to tell me, that I haven't unlocked it yet. I tried crafting it from collections, restarting the game, looking at Quest Kiosk, nothing. I assume it's a bug and I hope it gets fixed asap