[jQuery] $.getJSON() problem

[Aljosa Mohorovic]

i have a problem with $.getJSON(), nothing is logged in firebug
console although i can see that correct data is returned in response
(in firebug) for code:
>>>
$.getJSON(url, function(data){
    console.log(data);
});
<<<

same code, but using $.get instead $.getJSON works as expected:
>>>
$.get(url, function(data){
    console.log(data);
});
<<<

sometimes it works, but  i can't find where it breaks. also, firebug
doesn't report any errors.
any ideas or similar situations?

Aljosa