I've had similar issue but it only showed up after the anniversary update. My issue is I have nine different players in my reserves bench, players like 125 Guillit and others that I moved there to see if they would show up in my players under the signings section but ever since the anniversary update the only players that show up in under my players available are the players that I got during or after the release of the third anniversary. If I have a player that I got before the third anniversary on my reserve bench it says that they are in a lineup under the my players area of science. So I want to get the message card the new one and I can't because I can't sign these guys I don't need anymore because they are showing up as a lineup. Now everyone's going to say oh you probably got multiple lineups and he's probably in one of those but no I do not have multiple lineups. I only have one lineup and I have triple checked that