From Discord's age verification page, under "Privacy and Data Security":
Q: Is my data stored when I use Face Scan or Scan ID verification?
A: Discord and k-ID do not permanently store personal identity documents or your video selfies. The image of your identity document and the ID face match selfie are deleted directly after your age group is confirmed, and the video selfie used for facial age estimation never leaves your device.
So is that a lie?