No, it isn’t. We very recently discovered a bug that automatically sheathing your weapon and shield when looting a chest deactivates all bonuses on the shield (Phys/Elem armors, attributes, perks including luck). This functionality is intended to prevent imbalanced stacking of combat centric perks like crit chance. Actively using Sword and Shield to earn loot drops from combat is currently the only way to benefit from a luck bonus from the shield. We are prioritizing this issue against others and will aim to address it in a future release. The way it is intended to work is thus: If you have a sword and shield equipped and actively in your hands, and the shield has a luck perk associated with it, that luck should apply when looting chests if the sword and shield are active. If a shield is just equipped but sheathed on your back, the perks would not be active unless it was equipped in-hand with a sword.