Can't sell for shards

I have a 120 OVR base Gvardiol upgraded to 125 OVR, purchased directly from Star Signings.

I want to exchange him for Star Shards, but the game says he is still in a lineup.

I have removed him from all my regular lineups and Gauntlet squads. I have also reset Gauntlet matches and claimed all 45 stars.

He is the only player affected.

Please investigate and fix this issue so I can exchange my Gvardiol.

Thank you.