Last week I completed the associated objective (1,200 kills with rocket launchers or linear fusions) for unlocking the ability to focus Chosen Destruction engrams, while having 0 available Tier III engram focuses. The Prismatic Recaster acknowledged the completion, but the option to focus stayed locked, even after the reset and even after getting 5 hammer charges. I'm able to focus other Tier III engrams, but not this one.