As far as the pics are showing, it's only saying you own the exotic gear, not that you own the ornament. If you owned the ornament it would say "Already purchased on this account." in that first screenshot. You say you already got it one time. It's a Season of the Worthy ornament so the earliest time you could have got it was last season - and I don't believe it was in that season's engram meaning if you did get it, you would have had to purchase it from Eververse for Bright Dust or Silver. Could you be mistaken about your ownership, with that considered? Dismantling a gear piece that had it, should not have mattered.