I also have come across the re-appearing dusk items in my inventory upon login.This is what I've noticed:
- For me, the items only respawn in my inventory if I either destroy them, or put them in the party chest.
- If A) the items are equipped on a character or B) they are unequipped in my bags I have not seen this respawning bug occur. It only seems to occur if the I either destroy the items or put them in the party chest, then save/reload a game.
Hope that helps narrow it down

EDIT: Clarification on putting them in the party chest. The robes respawn after putting them into the party chest IF I then zone to a different area. If I stay in the area that the chest is in, the robes do not respawn no matter how many times I load.
Until a fix is found I've found the best thing to do is to just keep the stuff in my inventory when not equipped; never sell it, destroy it, or put it in the party chest. That's an extra 6-12 slots taken up but it beats deleting/selling the things on every login.
Edited by numark79, 13 September 2012 - 10:40 PM.