Why are there duplicate entries in Grub menu in Red Hat Enterprise Linux 7?

Issue

• Why are there duplicate entries in grub.cfg file? Every time it gets generated, there are these entries.

[root@rhel7 ~]# grep menuentry /boot/grub2/grub.cfg | grep class
menuentry 'Red Hat Enterprise Linux Server (3.10.0-327.28.2.el7.x86_64) 7.2 (Maipo)' --class red --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-327.28.2.el7.x86_64-advanced-9341171d-2dec-45ff-94d8-fdac7a4ed64b' {
menuentry 'Red Hat Enterprise Linux Server (3.10.0-327.el7.x86_64) 7.2 (Maipo)' --class red --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-327.el7.x86_64-advanced-9341171d-2dec-45ff-94d8-fdac7a4ed64b' {
menuentry 'Red Hat Enterprise Linux Server (0-rescue-0447976c1ce14258b0b4bd59d6ef0a5f) 7.2 (Maipo)' --class red --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-0-rescue-0447976c1ce14258b0b4bd59d6ef0a5f-advanced-9341171d-2dec-45ff-94d8-fdac7a4ed64b' {
menuentry 'Red Hat Enterprise Linux Server (3.10.0-327.28.2.el7.x86_64) 7.2 (Maipo)' --class red --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-327.28.2.el7.x86_64-advanced-9341171d-2dec-45ff-94d8-fdac7a4ed64b' {
menuentry 'Red Hat Enterprise Linux Server (3.10.0-327.el7.x86_64) 7.2 (Maipo)' --class red --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-327.el7.x86_64-advanced-9341171d-2dec-45ff-94d8-fdac7a4ed64b' {
menuentry 'Red Hat Enterprise Linux Server (0-rescue-0447976c1ce14258b0b4bd59d6ef0a5f) 7.2 (Maipo)' --class red --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-0-rescue-0447976c1ce14258b0b4bd59d6ef0a5f-advanced-9341171d-2dec-45ff-94d8-fdac7a4ed64b' {

• The first three entries are repeated.
• These entries exists even after creating the file of running config.

# grub2-mkconfig -o /tmp/grub.cfg