Seems to me a malformed caudatum. Exstaminodium should have much more globular pouch and darker color. If it repeat flowers without staminodial shield then it is a pale exstaminodium
It looks a lot like Phrag. Memoria Julius Dixler (caudatum x exstaminodium). The hybrid was made by one of our Chicago slipper orchid enthusiasts and registered in 2006.