I think its a combination of lack of players, too much money, and sellers who are clearly aware of the inflation (everyone talks about it!) setting higher prices than usual and getting them.
That's not a comment on the transfer you're talking about, I didn't see the player, but I think we've all similar situations on the transfer list. ITs been going on for a few seasons now, and I don't see an end to it.
On the plus side at least the players we currently have increase in value also.