I am experiencing the same issue. Received an exotic engram tonight and previewed the possible decryption options. Sweet business was one of the possibilities, unfortunately it did not happen. But, in the preview option it said that "sweet business" was in my collection, when I went to the vault it was not there. Is this something to do with the beta? I would really like to acquire this weapon as my skills are lacking and I need the best weapons I can get in order to compensate, yo.