Players wanting a new challenge at illogical times or without sufficient explanation

[crafty bison]

Does anyone else agree that this seems basically broken?

Two of my players have been repeatedly telling me all season that they want a new challenge. This comes in a season when we are properly challenging for the Premier League title for the first time, so it seems surprising that they feel they have achieved all they can. Tonight my left back took the biscuit - if we win our next game, we will secure the title, for the first time under my management (and the first time for this particular player). Less than one week before potentially winning the title, he comes to me yet again saying he feels he's achieved all he can.

This just doesn't make any sense? Or if it's driven by something else beyond the obvious, there needs to be more explanation of why it's happening. Too much in the player interaction model seems either nonsensical or unexplained (cf. my striker telling me there's no way he can continue under my management, and less than a week later his info screen telling me he's happy to be at the club. If things have changed, or he has a short attention span (!), or he's just a very reactionary kind of person - shouldn't I receive some indication?).