This bug is 100% reproducible for me.
I have purchased the spoon collection box in Lion’s Arch and was able to right-click and add the Carved Bone Spoon for the collection achievement.
Right-clicking or double-clicking either the Siege Commander’s Spoon or the Fractal Spoon causes my client to crash.
Repeatable “Unbound collectible item in non-locked set” errors with either spoon. I’ve tried right-clicking them with the item in one of the account/bank slots as well as right-clicking them when the items are in the character’s backpack slots. Either approach causes a client crash.