If you didn't claim the LFR or sidearm from the season pass during season of the Chosen, they will not drop from chosen focused umbral engrams. This feels like a huge gut punch during this season where there is a heavy emphasis on LFRs and sidearms. I wasted countless umbral engrams before realizing it's more than just bad luck. I know this issue has been brought up by multiple people now but I haven't seen any official acknowledgement from Bungie.