Found 3 or 4 reddit posts about it at the time I was searching for answers too. Not a single one of them had a solution, and I have never seen it acknowledged by bungie. Sorry, but unless this somehow gets 100+ upvotes, you are unlikely to get an answer because they quite simply don't care enough to even look at their own forums. If it makes you feel any better, you will eventually get a god roll sub machine gun and rocket launcher from that season, it just takes time. I think 4 or 5 of the engram focuses will remain forever bugged. Good luck!