It might well be but it happens in businesses all the time when cash flow is an issue. The only bills that will be getting paid will be those that absolutely need to be. The fact that the 'punishment' for late payment is a transfer embargo when we're outside a window is a flaw in the system that we seem to be taking advantage of. In the normal world, obviously the creditor would eventually go down a legal route to reclaim the money but I don't recall this happening between football clubs so maybe the FL tell them not to & we're happy to sit tight.
Of course Corney will be hoping that the FA Cup will alleviate some of these problems (who knows what plan B will be) but I suspect that, all being well, as soon as Sunderland indicate that they wish to proceed with the rumoured Edmundson transfer at some point in January, money will be found to lift the embargo for the time being.