Object Storage Retention
Obsolete restore points are removed from object storage automatically by Veeam Backup for Microsoft Office 365. Data removal is based on the retention policy settings that you configure when extending a backup repository with object storage.
Depending on how frequently your retention policy is configured to be executed, Veeam Backup for Microsoft Office 365 initiates a service task that calculates the age of offloaded restore points and if the age exceeds the specified retention period, this task purges obsolete restore points from object storage.
Do not remove anything from object storage manually, as this will irreversibly damage your backup structure to the point where you will be completely unable to read data from such corrupted backups.