When the on-premises protection software creates local backups, they are sent to the cloud. It’s important to make sure these local backups’ retention is set to a long-enough period to allow to send the files to the cloud. There might be an issue if you protect many large VMs with a short local retention configuration, and these files will be deleted from the local storage before all files could be sent to the cloud.
The cloud retention mechanism deletes copies from the S3 bucket on AWS or storage account on Azure, except if it’s the last available copy of a VM, and it will be deleted only after 30 days. The reason the last copy is still stored and not deleted based on the retention setting, is to support cases where there has been a connection shortage or a temporary protection issue and in order to avoid a full protection of the entire VM (instead of an incremental protection) to the cloud. For cases where you really need to remove all of the copies from the cloud, there’s an available workaround that could be applied by Dell support.