jeremywsherman,
Thank you for reaching out. It is expected behaviour that the one-time password won't autofill if you're using a passkey to sign in because a "fill session" wasn't started. Passkeys are separate from autofill as they use a public-private key pair for authentication. Rather than filling credentials into a form and creating a fill session, when you sign in with a passkey, the website or app will issue a challenge to check that you have the private key that belongs to the pair.
While I can't make any promises, I created a feature request on your behalf and shared your feedback with our product team so that when you use a passkey to sign in, the one-time password will autofill.
-Evon
ref:43174745