Rancher 2.5.2 - Restoring RKE from snapshot not working

We have an internal “private cloud” S3 storage array we’re using to dump our etcd backups. I’m seeing that our RKE cluster is dumping snapshots correctly to the S3 bucket, confirmed using AWS CLI with --endpoint-url pointing to our local S3 storage array, but using the UI to restore results in:

This cluster is currently Updating .

Failed to download etcd snapshot from s3, exit code [1]: time=“2020-11-11T02:59:59Z” level=fatal msg=“failed to download s3 backup: no backups found”

Is the UI honoring the endpoint URL setting for the S3 backup system when doing this?