It appears that block size is different in your two clusters . You can set flags -preserveBlockSize or -skipChecksum as below .
1. Suspend all Falcon jobs .
2. Modify template for falcon mirroring at /usr/hdp/current/falcon-server/data-mirroring/workflows/hdfs-replication-workflow.xml .Add the following argument at the end in argument list to preserve the block size .
3. Restart Falcon through Ambari.
4. Resubmit the job and verify if the HDFS mirror job is working fine now.
This will set this property for all mirror jobs.