Looking at the report . . . the only eyewitness reference to the JU-87 is in the part quoted above, from a radio operator. No gunner claims, no other eyewitness reports of JU-87s. And he describes the JU-87 as a "Stacey". I have never heard of this term before.
My take is that he was likely mistaken, but because the radio operator reported seeing JU-87 "Stacey dive bombers", it made it into the summary that JU-87s were present.
The claim is dubious IMO.
Never heard the Stuka referred to as a Stacey either, I think the radio operator was using Stacey in the phonetic to represent the S in Stuka.
I still agree with you that the event described probably didn't happen and the some type of Luftwaffe plane was misidentified as a Stuka. With the slow speed and relatively poor handling of the Stuka, especially at 20,000ft, you would have thought there would be at least some B-17 gunner reports of shooting down one or two Stukas but there isn't anything at all. Even in the other crew reports from that mission, none report seeing Ju 87s, only that one bomber.
I would like to see more verifiable evidence other than 'comments from the radio operator'.
ack-ack