Best in bags.
After locking in the nethercleft leg armor and a +12stam gem into my legs (used for tanking, dps is offspec) I get offered resilience or resilience+stam gems in some of my other items.
If you post a snapshot, we can take a closer look at your case. My guess is that the resilience is scoring well to reduce your chance to take critical hits. Instructions on how to make a snapshot here:
As Feral DPS you don’t really plan on tanking hits, that should be reserved for the Guardian profiles.
Snapshot: 415b79c9d97a4660a05d363c01a86e25
You have your feral dps spec set at a lower priority than your feral tank set (guardian). The tanking set wants to use the non-pvp bracers with a resilience gem, which makes them worse for your dps set than using the pvp item.
Locking in the stamina gem makes the optimizer pick up the resilience in the gem socket.