I've got this bug too unfortunately, for the tactics screen I choose to hide the players "Not at Club" to stop it being so congested. Especially considering how many players have left already lol
I still sometimes get training suggestions etc. for them though which is especially annoying so if anyone knows how to fix I would love to know (might just be a bug though).
I've read somewhere it might also be the skin used (I'm using the FM24 Zealand Skin)