So i noticed this recently. When you buy Kinetic Dash, you get the +10% weapon damage from it being a T2 weapon type item, but when you upgrade it to Arcane Surge, you lose the damage. My suggestion is to include passive item type bonuses in the stats when items switch their types(make arcane surge give +10% weapon damage for example). I know that this technically is not a bug, but it feels weird to LOSE something when UPGRADING the item.