I think it might be a typo. The list of (Geschwader)Stab./JG3, reference Jochen Prien 'Bf109 im Einsatz bei Stab und I.JG3/Erik Mombeeck 'Missing in action'):
- Fw 190A-8, W-Nr. 172699, code red 21, piloted by Oberfähnrich Siegfried Clement (KIA), lost in combat near Caen/Normandy on july
24th 1944