Workaround:
If there are several Windows Recovery Environment volumes in the system, please assign drive letters to all of volumes. To assign drive letters to them, use DISKPART command. (See below.)
After assigning them and creating new backup jobs, please back up again.

For instance:

(Disk partition 4) - Windows Recovery Environment - 990 MB
(Disk partition 5) - Windows Recovery Environment - 12 GB
(Disk partition 6) - Windows Recovery Environment - 1.5 GB

c:> diskpart

DISKPART> select disk 0

DISKPART> list volume

NOTE: Check volume number and size. Find the volumes that have 990 MB, 12 GB, 1.5 GB.

DISKPART> select volume X

NOTE: X is volume number for 990 MB. If the volume number is 3, run "select volume 3".

DISKPART> assign letter=L

NOTE: Assign 990MB volume to L drive.

DISKPART> select volume Y

NOTE: Y is volume number for 12 GB. If the volume number is 4, run "select volume 4".

DISKPART> assign letter=M

NOTE: Assign 14.12GB volume to M drive.

DISKPART> select volume Z

NOTE: Z is volume number for 1.5 GB. If the volume number is 5, run "select volume 5".

DISKPART> assign letter=N

NOTE: Assign 1.5 GB volume to N drive.

DISKPART> exit

C:\> exit

Backup Exec System Recovery has acknowledged that the above-mentioned issue is present in the current version(s) of the product(s) mentioned at the end of this article. Backup Exec System Recovery is committed to product quality and satisfied customers.
 
This issue is currently under investigation by Backup Exec System Recovery. Pending the outcome of the investigation, this issue may be resolved by way of a patch or hotfix in current or future revisions of the software. However, this particular issue is not currently scheduled for any release. If you feel this issue has a direct business impact for you and your continued use of the product, please contact your Backup Exec System Recovery Sales representative or the Backup Exec System Recovery Sales group to discuss these concerns.  For information on how to contact Backup Exec System Recovery Sales, please see https://supportbackupexec.cloud.com/ Please be sure to refer back to this document periodically as any changes to the status of the issue will be reflected here.