I recognized those screens, I'm using CodeFluentEntities, and I've got solution that worked for me as well.
I'm using that construction:
$.ajax({
url: path,
type: "POST",
contentType: "text/plain",
data: {"some":"some"}
}
as you can see, if I use
contentType: "",
or
contentType: "text/plain", //chrome
Everything works fine.
I'm not 100% sure that it's all that you need, cause I've also changed headers.