jQuery strange caching behaviour on IE8 beta

I hate javascript. And the more you hate it, the more you'll like jQuery. Usually it shelves us from browser implementations, this time it didn't.

I have a standard pair of dropdowns with depending values I'm loading with jQuery. Something like:

                $.getJSON(
                    "myJsonService",
                    "ID=" + $(dropdownlistFrom).val(),
                    function(data) {
                        $(dropdownlistFrom).fillSelect(data);
                    }
                );

On Firefox all works as expected. But on IE8 beta, it activates the caching mechanism! I had to rewrite it to something like:

                $.ajax({
                    url: "myJsonService",
                    cache: false,
                    dataType: "json",
                    success: function(data) {
                        $("dropdownTo").fillSelect(data);
                    },
                    data: "ID=" + $("dropdownFrom").val()
                });

I've also tested on Chrome and Opera working as expected, not caching the data.

Finally I've tested on Safari 3 on Windows, and it just didn't work, cache or no cache! Strange, as jQuery should work on Safari.

Man, I hate javascript...