S3 CRR and objects locks

A customer is building a DR architecture, using S3 CRR to copy its data to another region. All the infra is replicated (at small scale) in the DR region.

The source S3 bucket is accessed by a SFTP server doing read/write operations. So there is another SFTP server in the DR region, pointing to the CRR bucket, ready to take over if DR occurs.

Question:

Is there any kind of locking on the CRR done by the CRR process, preventing access from the DR SFTP server to the CRR bucket ?