Hourly storage.php Undefined offset set of messages since a NFS share was defined on fstab for Backup

I’m not definitely sure about that timeline but, looking at freepbx.log timeline and comparing that one with the one of yum.log (used for nfs client install, if I don’t recall bad), since I defined a newly created NFS share mount point on the fstab (for remote backup) and since I then set a full backup daily task of FreePBX on that destination (it’s on a NFS share on a NAS) I discovered an hourly recurring set of five PHP Notice messages on the freepbx.log which was not present before:

[2013-Dec-19 19:00:01] [PHP-NOTICE] (/var/www/html/admin/modules/sysadmin/functions.inc/storage.php:96) - Undefined offset: 1 [2013-Dec-19 19:00:01] [PHP-NOTICE] (/var/www/html/admin/modules/sysadmin/functions.inc/storage.php:97) - Undefined offset: 2 [2013-Dec-19 19:00:01] [PHP-NOTICE] (/var/www/html/admin/modules/sysadmin/functions.inc/storage.php:98) - Undefined offset: 3 [2013-Dec-19 19:00:01] [PHP-NOTICE] (/var/www/html/admin/modules/sysadmin/functions.inc/storage.php:99) - Undefined offset: 4 [2013-Dec-19 19:00:01] [PHP-NOTICE] (/var/www/html/admin/modules/sysadmin/functions.inc/storage.php:100) - Undefined offset: 5 [2013-Dec-19 20:00:02] [PHP-NOTICE] (/var/www/html/admin/modules/sysadmin/functions.inc/storage.php:96) - Undefined offset: 1 [2013-Dec-19 20:00:02] [PHP-NOTICE] (/var/www/html/admin/modules/sysadmin/functions.inc/storage.php:97) - Undefined offset: 2 [2013-Dec-19 20:00:02] [PHP-NOTICE] (/var/www/html/admin/modules/sysadmin/functions.inc/storage.php:98) - Undefined offset: 3 [2013-Dec-19 20:00:02] [PHP-NOTICE] (/var/www/html/admin/modules/sysadmin/functions.inc/storage.php:99) - Undefined offset: 4 [2013-Dec-19 20:00:02] [PHP-NOTICE] (/var/www/html/admin/modules/sysadmin/functions.inc/storage.php:100) - Undefined offset: 5 [2013-Dec-19 21:00:02] [PHP-NOTICE] (/var/www/html/admin/modules/sysadmin/functions.inc/storage.php:96) - Undefined offset: 1 [2013-Dec-19 21:00:02] [PHP-NOTICE] (/var/www/html/admin/modules/sysadmin/functions.inc/storage.php:97) - Undefined offset: 2 [2013-Dec-19 21:00:02] [PHP-NOTICE] (/var/www/html/admin/modules/sysadmin/functions.inc/storage.php:98) - Undefined offset: 3 [2013-Dec-19 21:00:02] [PHP-NOTICE] (/var/www/html/admin/modules/sysadmin/functions.inc/storage.php:99) - Undefined offset: 4 [2013-Dec-19 21:00:02] [PHP-NOTICE] (/var/www/html/admin/modules/sysadmin/functions.inc/storage.php:100) - Undefined offset: 5

Is that normal?

The backup task ends normally overnight (at 00:00 every day, about 43 MB of FreePBX full backup everyday) and the NFS share mount point appears OK from a filesystem point of view (mounted and able to be browsed/accessed by asterisk user).

The system is FreePBX Distro 4.211.64-10, updated (SysAdmin Pro).