if data is stored for an element twice with a hyphenated property, cache stores two properties one hyphenated and one camel case. If you call removeData one property is removed. Therefore if you get the data value is returned when this should be undefined

$("#element").data("my-key", { id: 0; value: "Value0" });
$("#element").data("my-key", { id: 1; value: "Value1" });
$("#element").removeData("my-key");
$("#element").data("my-key"); //return { id: 1; value: "Value1" } when sholud be 'undefinded'