[CentOS] yum warning...

Thu Jan 5 14:17:17 UTC 2012
John Doe <jdmls at yahoo.com>

Hey,

From time to time I catch a yum warning.
Last time it was today:

# yum update

...

Downloading Packages:
vsftpd-2.2.2-6.el6_2.1.x86_64.rpm                                 | 149 kB     00:01     
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
Warning: RPMDB altered outside of yum.
  Updating   : vsftpd-2.2.2-6.el6_2.1.x86_64                                         1/2 
  Cleanup    : vsftpd-2.2.2-6.el6_0.1.x86_64                                         2/2 
Updated:
  vsftpd.x86_64 0:2.2.2-6.el6_2.1                                                                   
Complete!

How come a simple update of a a single package from CentOS update 

would "alter RPMDB outside of yum"...?
Could that be a plugin?
  yum-3.2.29-22.el6.centos.noarch
  yum-metadata-parser-1.1.2-16.el6.x86_64
  yum-plugin-fastestmirror-1.1.30-10.el6.noarch
  yum-plugin-priorities-1.1.30-10.el6.noarch
  yum-utils-1.1.30-10.el6.noarch

Anyone else?


Thx,
JD