I think Dammit said almost all items are up on GT in latest update day or two ago. Which means there are one or two still hidden - probably just one. It would be safe to assume the eluding secret one is hidden for now, which would mean if it is on GT now the item in question probably isn’t part of the secret that is missing. Otherwise Zantai would have confirmed it by now
In fact, to quote Dammitt from April 2nd: