Prior to D-Day, no officer below planning level knew of the D-Day plans, individuals with the classification 'BIGOT'.
No 'BIGOT' officer was allowed on operations prior to D-Day and few left operational headquarters.
Even if the Germans had captured the entire force of 'Operation Tiger' they would have learned nothing more than those officers knew, which was zero.
D-Day planning, 'OVERLORD', was immaculate and the security operation alongside it, "BODYGUARD", "FORTITUDE" and a dozen others, was run by the clever British and not the incompetent nazis nor leaky us-forces.
Many officers, if they knew anything 'were misled to suspect' they were part of a 'diversionary attack' in the 'Normandy region' and only when aboard ship, on the day, off the French coast, did they look around them at the thousands of ships and naval vessels and suddenly realize they were the main force. War Diaries attest to this for many, even senior, commanders.
Luckily, your story fails at paragraph one!