Incremental backups are running against a path that contains files that are copied to this path. A new directory is created to hold these files. A new incremental backup is done after these files were backed up, but they were backed up previously from a different directory.
NetBackup sees the new directory and will backup the files because the directory is new. When a new directory is created, NetBackup will backup the contents of the directory since it was not backed up in the last backup. This is normal behavior for Netbackup
If i copied the backup files to a newly created directory.then including the directory all the files in it will be backed up in INCR and FULL