So this is something I was rather devastated by. I reached tier 3 and was finally able to switch to a full set of tier 3 gear from my chaos dungeon runs. However, after unequipping all my tier 2 gear to sell on the auction house, the game told me some items were on a different preset and thus to switch presets before selling. However, when I did this, I also started dismantling my excess drops and in doing so, dismantled part of my original set of tier 3 gear that was already equipped in the first preset. I feel like this has to be a bug: the game will forbid me from selling gear on the auction house that is equipped in another preset, but it has no problems with me dismantling gear in that is equipped in another preset. As you can see in the screenshot below, I did hit 1304 gear score, but I ended up dismantling the original tier 3 pauldrons that were already equipped (not only the pauldrons but also multiple earrings and rings were dismantled so this is not a one-time occurrence).