Had a quick look at the info I have for this aircraft and it shows the flight to be the 2nd Aug 1944. Unit was 73OTU aircraft a Kittyhawk Ia (P-40E-1).

His death certificate would have been produced before the aircraft (maybe – looking into this now) and pilot where found and therefore will have been dated on the presumed death date of the 2nd Aug 1944. If after the fact someone requested a new Death Certificate then the date would have been amended.

Buz