Had a Haunted Memento in my bags prior to TWW, swapped over to that character and the Haunted Memento has disappeared and was not sold or destroyed. Just vanished into the nether. Unfortunately this is not an item that one can just easily replace because it is from the TBC pre-patch and sells for over a million gold on most servers.
Well, dang.
I checked my characters after seeing this and mine are gone, too. I had four and now I have only one, on a character I haven’t touched in years.
I have an inventory addon that tracks across alts, so I definitely didn’t misplace them. But they also haven’t left my bags since I got them years and years ago so it would be pretty weird timing if I suddenly had on everyone.