PowerProtect Data Manager: FS Backup Fails Inconsistently for Volume Partition

Affected versions: 
19.12 and 19.13

Affected Configuration and Settings: 
This issue is specific to File System Volume Partition Backup Configuration (BBB Backup) only.

Affect on PowerProtect Data Manager: 
Issue on PowerProtect Data Manager shows as it shows as failure status.

Symptoms found in the logs: 
This issue shows through logs by garbage characters in log message, and also through debugging. 

Scheduled backups fail while every step reports as successful. You see that backup copies are valid. 
If you manually run the policy, the UI always reports the backups as having completed successfully, but the next scheduled backup may report as failed.

Root cause: 
The issue shows in BBB Backup when any of the files being excluded from the backup delete from the snapshot.
Sometimes the excluded files may not be present in the snapshot. In this case, a log message is printed and sent from the nsrwriter.exe to the ddfscon layer. This is why it is added to the JSON output for the backup.
While sending you use the msg_print() function which internally converts utf8 format message to multi-byte string format. This fails to insert into the JSON output. This causes the backup to fail.