Unable to retrieve GetFaceLivenessSessionResults if the Session Expires

Hello,

We're trialing the new Face Liveness offering with AWS Rekognition. However we've found a potential issue that might cause serious implementation problems.

After a liveness session is completed, we noticed the only way to retrieve the results is through the GetFaceLivenessSessionResults endpoint with the corresponding Session ID of the liveness session.

That's fine, and we can see the frontend SDK also has a callback that provides these results.

However, what we have noticed is that sessions are short lived, and we're unable to retrieve the results from the endpoint after a few minutes.

This is very concerning to us for several reasons:

1. There are no webhooks or EventBridge events to subscribe to on Liveness Session Results, so we're restricted to relying on a frontend event to call our API to allow us to persist these results for an audit trail.
2. Because there are no backend webhoks or events to subscribe to, we're at the mercy of the client's network connectivity to inform our API when to retrieve and store the results before the session expires.
3. In the event of any outage or delay either by AWS or on our side, it's very possible that sessions can expire before we can retrieve results. This would be a terrible user experience, they go through the friction of completing a liveness check, only to be asked to do it again.

Can the results be included with the reference and audit images in the S3 bucket? Or at least change the authentication strategy for this route in particular to allow our API to retrieve any result from any session performed with our account?

We're paying for these liveness checks individually, so we expect to be able to access the results we paid for, not just within a small fragile window.

I hope this makes sense, please let me know if I'm missing an API endpoint or crucial detail.