Legally, the claim was lost when Andreas Palaiologos auctioned it off to the Catholic Kings
From WP: "Andreas died a pauper during 1502, in spite of having sold his titles and royal and imperial rights again to Ferdinand II of Aragon and Isabella I of Castile. However, Runciman doubts he ever received any money due, for his widow had to beg the Pope for 104 ducats to pay the costs of his funeral."
Ok, so maybe they forgot to pay him for the claim... but the Catholic Kings got it anyway!
(Also, apparently Andreas' wife had approved Papal Investiture)
Yes BUT they officially renounced the title some generations later, so... nothing to see there
Seeing that they weren't using it, Andreas had every right to sell the title again to someone else! Anyway, it's not like "selling claims of Empires you don't control to vaguely amused kings" has very strict rules.