why HOOK-pkgdowngrades: ERROR: Multiple packages

Hi,
I am trying to do RHEL OS upgrade from 6.8 to 7.3
I got the following error when redhat-upgrade-tool was executed.

for example,

HOOK-pkgdowngrades: INFO: start with arguments: /root/preupgrade/pkgdowngrades/enforce_downgraded --destdir=/root/preupgrade/pkgdowngrades/rpms --installroot=/root/preupgrade/pkgdowngrades/installroot --rhelupdir=/var/lib/system-upgrade
Loaded plugins: product-id, refresh-packagekit
No plugin match for: rhnplugin
Loaded plugins: product-id, refresh-packagekit
HOOK-pkgdowngrades: ERROR: Multiple packages: ncurses-base.noarch ncurses-base.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: system-config-keyboard-base.noarch system-config-keyboard-base.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: python-magic.noarch python-magic.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: system-config-keyboard.noarch system-config-keyboard.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-Pod-Escapes.noarch perl-Pod-Escapes.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-Module-Pluggable.noarch perl-Module-Pluggable.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-Pod-Simple.noarch perl-Pod-Simple.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-Locale-Maketext-Simple.noarch perl-Locale-Maketext-Simple.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-Params-Check.noarch perl-Params-Check.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-Module-Load.noarch perl-Module-Load.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-Module-Load-Conditional.noarch perl-Module-Load-Conditional.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-Log-Message.noarch perl-Log-Message.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-Package-Constants.noarch perl-Package-Constants.noarch
HOOK-pkgdowngrades: WARNING: package 'hwdata' is not noarch anymore, x86_64 will be installed
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-IO-Zlib.noarch perl-IO-Zlib.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-Archive-Tar.noarch perl-Archive-Tar.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-Log-Message-Simple.noarch perl-Log-Message-Simple.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-Term-UI.noarch perl-Term-UI.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-Object-Accessor.noarch perl-Object-Accessor.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-Module-CoreList.noarch perl-Module-CoreList.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-Module-Loaded.noarch perl-Module-Loaded.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-Parse-CPAN-Meta.noarch perl-Parse-CPAN-Meta.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-parent.noarch perl-parent.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-CGI.noarch perl-CGI.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-Test-Harness.noarch perl-Test-Harness.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-ExtUtils-MakeMaker.noarch perl-ExtUtils-MakeMaker.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-ExtUtils-ParseXS.noarch perl-ExtUtils-ParseXS.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-IPC-Cmd.noarch perl-IPC-Cmd.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-File-Fetch.noarch perl-File-Fetch.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-Archive-Extract.noarch perl-Archive-Extract.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-ExtUtils-CBuilder.noarch perl-ExtUtils-CBuilder.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-Module-Build.noarch perl-Module-Build.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-CPANPLUS.noarch perl-CPANPLUS.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-Test-Simple.noarch perl-Test-Simple.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-ExtUtils-Embed.noarch perl-ExtUtils-Embed.noarch
HOOK-pkgdowngrades: ERROR: Multiple packages: perl-CPAN.noarch perl-CPAN.noarch
HOOK-pkgdowngrades: WARNING: package 'dracut' is not noarch anymore, x86_64 will be installed
HOOK-pkgdowngrades: ERROR: Multiple packages: samba-common.noarch samba-common.noarch

could you please tell me whether it has impact on the upgrade?
why does redhat-upgrade-tool raise this ERROR out?

Regards
Zhong