If you draw Hidden Cache as one of the two cards for Cirdan’s ability and choose that as the card to be discarded, do you get the resources? My initial thought was no, but the ruling on King Under the Mountain has made me unsure. I get the wording is slightly different, but at what point is it no longer in your deck?

I think it does

At the point where Cirdan's Forced effect causes the card to be discarded, it's in your hand rather than your deck. So effects that care about being discarded from the deck don't trigger, and effects that care about being discarded from your hand do trigger.

22 minutes ago, NathanH said:

At the point where Cirdan's Forced effect causes the card to be discarded, it's in your hand rather than your deck. So effects that care about being discarded from the deck don't trigger, and effects that care about being discarded from your hand do trigger.

Reading the cards, you are totally correct. Never used hidden cache in cirdan deck, I forgot the correct interaction between the 2 cards. Apologize for the wrong answer!