While the labels are clearly stating 20 GB, there is nothing else attesting to the actual VRAM capacity of these cards. These are probably some mislabeled models that still pack 12 GB, but just imagine the ridiculous prices asked by retailers if 20 GB models were indeed real.
https://www.notebookcheck.net/Nvidia-GeForce-RTX-3080-Ti-cards-with-20-GB-VRAM-spotted-in-Russia-might-only-be-some-mislabeled-models.557045.0.html