Vlad this is not related to native passkey support, as Proton Pass uses its own implementation for passkeys. The issue is WebKit specific, as the credential options received to web-extension, due to change in content world(WebExtensions scripts gets executed in sandboxed environment and not in page directly), the ownership of original instance becomes unacceptable for the web-extension and checking e instanceOf ArrayBuffer returns false in Proton Pass script and that causes the action to fail and produce the exception.
For now there's no direct fix, as this is due to how WebKit behaves, so I uploaded patched version of Proton Pass to our CDN and can be installed directly from Orion's Popular Extensions.
