These exercises were before my time, actually when I was still a little guy, dreaming about flying.
I don’t remember ever hearing about these Vulcan “ attacks” during my time in the air defense world. ECM was and is a key player in modern air combat. Hard to say what circumstances were for the Vulcan penetrations. Could have been a combination of factors but, still embarrassing. Thus, the need for “CLASSIFICATION”.
The Vulcans at high altitude were in the heart of the envelope for the F-106 which was designed as a high altitude supersonic interceptor. I’ll query some of my old head 106 contacts and see if they can shed some light on this.