[CentOS] How can rpm "%{SUMMARY}" not be consistent?

I have been seeing something for quite some time which has confused me
considerably for over a year, perhaps one of you can help me understand.

Assumed: rpm queries are against _a_ database.
Assumed: database queries against the same database, without changes to
the data in the database, will return the same data.

Confusion: then why are some of the summaries reported by rpm different?

Each day I (cron.daily) run the following command
rpm -qa \
     --qf
'"%{VENDOR}","%{NAME}","%{VERSION}","%{VERSION}-%{RELEASE}","%{ARCH}","%
{SUMMARY}"\n' \
  | sort -t\" -k3 > ${OUTFILE}

Stuff the resulting ${OUTFILE} in an rcs file.

And some days the rcs file will show deltas such as the following (which
was pulled from a rather recent set of flipflops):

--- mach.csv    2011/11/15 10:50:04     
+++ mach.csv    2011/11/15 09:22:53 

-"CentOS","bash","3.2","3.2-32.el5","i386","The GNU Bourne Again shell
(bash) version 3.1."
+"CentOS","bash","3.2","3.2-32.el5","i386","The GNU Bourne Again shell
(bash) version 3.2"

-"CentOS","compat-db","4.2.52","4.2.52-5.1","i386","The Berkeley DB
database library for CentOS 2.1 compatibility."
+"CentOS","compat-db","4.2.52","4.2.52-5.1","i386","The Berkeley DB
database library for Red Hat Linux 7.x compatibility."

-"CentOS","firefox","3.6.24","3.6.24-3.el5.centos","i386","Mozilla
Firefox Web browser."
+"CentOS","firefox","3.6.24","3.6.24-3.el5.centos","i386","Mozilla
Firefox Web browser"

-"Adobe Systems
Inc.","flash-plugin","11.1.102.55","11.1.102.55-release","i386","Adobe
Flash Player 7.0"
+"Adobe Systems
Inc.","flash-plugin","11.1.102.55","11.1.102.55-release","i386","Adobe
Flash Player 11.1"

-"CentOS","gdb","7.0.1","7.0.1-37.el5_7.1","i386","A GNU source-level
debugger for C, C++, Java and other languages."
+"CentOS","gdb","7.0.1","7.0.1-37.el5_7.1","i386","A GNU source-level
debugger for C, C++, Java and other languages"

-"CentOS","gettext","0.17","0.17-1.el5","i386","GNU libraries and
utilities for producing multi-lingual messages."
+"CentOS","gettext","0.17","0.17-1.el5","i386","GNU libraries and
utilities for producing multi-lingual messages"

-"CentOS","htmlview","4.0.0","4.0.0-2.el5","noarch","Tools for launching
Preferred Applications"
+"CentOS","htmlview","4.0.0","4.0.0-2.el5","noarch","Launcher of
Preferred Web Browser"

rpm -q --last compat-db htmlview
compat-db-4.2.52-5.1                          Tue 17 Mar 2009 02:32:59
PM EDT
htmlview-4.0.0-2.el5                          Tue 17 Mar 2009 02:21:59
PM EDT
i.e. these have been there, at this version, since machine install.

poking around in /var/lib/rpm/, with strings and grep, the only file I
find "Adobe Flash Player " in is Packages and I only find the "Adobe
Flash Player 11.1" variant of the string.
Yet at the same time
rpm -q \
 --qf
'"%{VENDOR}","%{NAME}","%{VERSION}","%{VERSION}-%{RELEASE}","%{ARCH}","%
{SUMMARY}"\n' \
 flash-plugin 

displays:
"Adobe Systems
Inc.","flash-plugin","11.1.102.55","11.1.102.55-release","i386","Adobe
Flash Player 7.0"

/var/tmp/rpm* is nonexistent.

Note: rpm does seem to be fairly consistent in its inconsistency, the
above applications are a small sampling of a larger *set* (out of ~180
packages that show this) that seems to keep flip flopping from one
SUMMARY to the other, *usually* in the day or two post a yum update (not
sure if reboots also affect it). 
The summaries always bounce between the same text, i.e., htmlview has
always used either "Launcher of Preferred Web Browser" or "Tools for
launching Preferred Applications" and bash has always used either "The
GNU Bourne Again shell (bash) version 3.1." or "The GNU Bourne Again
shell (bash) version 3.2" (and a 3.1 version has never been installed on
the system).

RHEL machines show the same flip flops with the same packages and same
flopping summary texts.

So where is rpm getting the bad information from?????
Can it be cleaned out? What would be lost by cleaning it out?