Radio button groups must be established when "They both have a name attribute, their name attributes are not empty, and the value of a's name attribute is a compatibility caseless match for the value of b's name attribute." See https://html.spec.whatwg.org/multipage/forms.html#radio-button-group This bug was found by the newly added test: LayoutTests/http/tests/w3c/html/semantics/forms/the-input-element/radio-groupname-case.html
<rdar://problem/22589518>