Some people have experienced a delay in the update of their unlocked game engrams. Due to an unprecedented demand, which has created a high level of traffic, the system may take a bit longer to update in your account.
In most cases, this can be updated by logging out of your Bungie.net, and then back in, this should refresh the status of your account. It can sometimes take up to 10 mins, so please be patient.
More information regarding Bungie.net In-Game content