I don't understand Turkish, but according to google translate the original tweet says "Galatasaray reached an agreement with Lucas Digne and made an official offer to Aston Villa. Cenk Ergün started negotiations with Monchi."
Maybe they haven't reached an agreement with Digne and just stuck an offer in?
I don't know if that even happens nowadays to be honest. You're not really supposed to talk to clubs until an offer has been made or accepted according to "tapping up" rules but obviously clubs, players and agents don't stick to that. Bit of a waste of time preparing and making an offer if it turned out a player wasn't interested.
A long time ago I remember Solskjaer having an offer accepted by United from Spurs. That was unsolicited and he turned them down, wanting to stay with us.