The Cryptarch will not be able to decode these engrams until May 19th. Hold on to them until then. Bungie has posted about this in their [url=https://www.bungie.net/en/Forum/Post/121703802/0/0]1.2.0 Updates[/url] thread: [quote]-Engrams: All Legendary Engrams, as well as Rare Engrams, acquired from the Crucible and the new Fallen Public Event chests will not be recognized by the Cryptarch. Solution: Hold on to all newly-acquired Engrams of pertinent quality until May 19th to benefit from their upgraded decryption skill-set. [/quote]