Well with Fracture while the DoT is increased. That's not actually doubling the damage. Since it's 15s + 100 potency at the start. At 20 potency a tick and a tick being every 3s, the trait only adds 100 potency. Thats a 50% improvement.
I thought maybe because there are other sources saying that its 10% it may just be that the in-game text might be false so wanted to see if anyone confirmed. Since well 5-20% is like 4x better and most traits don't make a skill 4x better which is why I wondered if it was a mistake.