Signature Exchange Bug

Hello, I need help with the Signature Exchange for Lampard in FC Mobile. I am trying to exchange my 120 Lampard for the 126 Lampard. The requirement shows I have 3 Signature Tokens, but I cannot tap or select the token slot. It does not open the selection window, and the exchange button remains grayed out even after clearing slots, restarting the game, and making sure no version of Lampard is in any of my active lineups. Please help look into this token issue. Thank you.