In a similar style i found out that if i wasn't supposed to have enough money for a players demand, i would not have enough no matter what, when offering a contract.
Tried to edit the budget as well, but the player always wanted just a bit too much all the time.
Didn't matter if i increased or decreased the wage budget. The player would change his demand accordingly. Result being i was always short of his demand
This is on 10.3 and it's not just one player. It happens quite frequently.
And i'm still not able to give players a sign-on fee at random times. More often than i can give them one.