Short version: condition duration items and stats do nothing/are bugged.
Long version: I was excited to see the introduction of condition duration gear when I found a recipe for Giver’s Orichalcum-Imbued Inscription in a gift today. I gave it to my Artificer and immediately made an 80 exotic “Giver’s Pearl Rod” (scepter) for the purposes of testing, and what I had hoped was use. To test it I equipped it, of course, on my 80 Necromancer. Dummies in Lion’s Arch cannot be inflicted with conditions and so I sought various random mobs in different locations test the effects. Tooltips remained unchanged, but they are commonly inaccurate anyway. What I found bothered me: condition duration was unaffected by the new scepter. I made certain that it was not being overridden or conflicted by other sources through repeated tests. Normally I have 20% condition duration from traits, 4% and 6% from Nightmare rune bonuses, and 10% bleed duration from an offhand Sigil of Agony. Testing proved that all of these sources stack together nicely, on weapon and utility skills which inflicted conditions. But even naked and traitless I was unable to receive any benefit from the 10% condition duration listed for a “Giver’s” 1hand weapon: it’s not interfering with anything; it just provides no benefit at all.
I was tempted to do more tests with other weapons/classes to confirm if this is the fault of a specific item/class, but it’ll cost me more and benefit me none until it is fixed. I hope it is fixed, as condition duration (and boon duration from armor as far as I know) seem like niche stats which would make a fun addition to certain builds in the future. Hope this helps, and happy Wintersday.