Version:           1.10.3 (using 4.1.3 (KDE 4.1.3), Kubuntu packages)
Compiler:          cc
OS:                Linux (i686) release 2.6.24-22-generic

An example is better than my own words.  These are the headers that yahoo.com email has for a Walmart advertisement:

Return-Path:   	 	 <walmart@newsletters.walmart.com>
Authentication-Results: 		mta271.mail.mud.yahoo.com from=newsletters.walmart.com; domainkeys=pass (ok) ; from=newsletters.walmart.com; dkim=neutral (no sig)
Received: 		from 72.5.68.133 (HELO mx-v11.gm.mail.yahoo.com) (72.5.68.133) by mta271.mail.mud.yahoo.com with SMTP; Thu, 27 Nov 2008 13:33:56 -0800
Transit-DomainKey-Signature: 		a=rsa-sha1; q=dns; c=nofws; s=transit_gm2; d=yahoo.goodmailsystems.com; h=X-Originating-IP:X-YahooSRV:X-GoodmailSystems-Canceled:Received:X-GoodmailSystems:X-GoodmailSystems-Rcpto:X-GoodmailSystems-Cert:X-GoodmailSystems-Entity:X-GoodmailSystems-Sig:DomainKey-Signature:X-Habeas-Report:Reply-To:Bounces_to:Message-ID:X-BFI:Date:From:Subject:To:MIME-Version:Content-Type; b=dZOcRi3j5CK61uMZmoSOJYczPLLvSED2TwnpaRtpMxnqPoEz5kasI9O2OXPlT+++HPfiWZemd1SjCOgHFXYYHTAInjuoDGRcMk/g6CevUiFvrB6R9ygn2TGeGtSDs0aaETJ4udtbzYDXco2Ziy2Pkl1qAweCAfuYh/+t5JpGz04= ;
Received: 		from arm226.bigfootinteractive.com (HELO bigfootinteractive.com) (206.132.3.226) by ycgw47.sjc.mta.yahoo.com with SMTP; 27 Nov 2008 21:33:43 -0000 s="000063020000630200000001492F11E26F09044E000511920000001200000001"; e="20081130T213218"; d="20081127T213218"; o="15243"; t="0"; p="4"; h="SERgz3WQDAl86Yv/0Saf6YdaiNo="; b="3DyZmW2fUJRdn4njJsGajPEMO7k="; f="PT9pc28tODg1OS0xP0I/VjJGc2JXRnlkQ0JYYVhKbD89IDx3YWxtYXJ0QG5ld3NsZXR0ZXJzLndhb G1hcnQuY29tPg=="; I="001002000"; VU0NBOlgtR29vZG1haWxTeXN0ZW1zMB4XDTA4MTEwMTAwMDAwMFoXDTA5MDgwMTAwMDAwMFowgYkxCzA JBgNVBAYTAlVTMQswCQYDVQQIEwJDQTEWMBQGA1UEBxMNTW91bnRhaW4gVmlldzERMA8GA1UEChMIR29 vZG1haWwxDDAKBgNVBAsTA09wczEMMAoGA1UEAxMDT3BzMSYwJAYJKoZIhvcNAQkBFhdvcHNAZ29vZG1 haWxzeXN0ZW1zLmNvbTB8MA0GCSqGSIb3DQEBAQUAA2sAMGgCYQC3887/bsJFUMJOuV9VXge1q0sxeak Mv9FsR+hdbWrCXW/VxADMCZ9sneXD65aSwiudwudxUue+2Iq7Sa9Jp0grv8p5ghR/+0j878w9bTrEovt SA+UwVb0K0JLzRtVG0HECAwEAATANBgkqhkiG9w0BAQUFAAOCAQEAVip+7RsAot+UuRznv13MwSr6lV+ Nggm/1Jj7+aBV3lswaeterJV+dy1DTG50ix+rKfcCCfH3uR6CbrxXn/ZSx+YLacOpAoUuA2pAmnSxSGM 8KS254fQ6VTSXC4MWQ8Ei48IRNMQEbdGkCXu9q+4Ktdy1lnNwfXz9cT71i9EcAzJERJW8qNovor8TCT4 yEUAOO4u4OdKBnYSdy4+iSS/njpNehJS0koCOe6Twnfros+DL856KTNffKN0GZmXsZhBZvf8o3JModp9 8pWSY4lct/8TR1T6fBDTW1q1xx04OcDQSjq3gb5PbSbwl62wmmN6O2MZEfwxl0XSWxg9h5Dp7VA== c5x5UHNxZwem7AYwJ43xHq6YsDdUtJUovtEaPI9OmdyA3omtBorYfiNEsjtYdBRYfSr0IyyJ
DomainKey-Signature: 		a=rsa-sha1; q=dns; c=nofws; s=bfi; d=newsletters.walmart.com; b=g2/uZOw19JuAeWQXiC7Z1jGcD603bAIKhNydV6WnI2utsiDlhiYVNB3X9IL9mhqw;
Reply-To: 		walmart.W0TH05302446C012CCC782EDD0DA30@newsletters.walmart.com
Bounces_to: 		walmart@newsletters.walmart.com
Message-ID: 		<W0TH05302446C012CCC782EDD0DA30.6849.7747.pimailer52.DumpShot.1@newsletters.walmart.com>
Date: 		Thu, 27 Nov 2008 16:32:17 EST
From: 		This sender is DomainKeys verified
=?iso-8859-1?B?V2FsbWFydCBXaXJl?= <walmart@newsletters.walmart.com>  
Add sender to Contacts
Subject: 		=?iso-8859-1?B?VGhhbmtzZ2l2aW5nIERheSBTcGVjaWFscyArIERvbid0IE1pc3MgRnJpZGF5J3MgSW4tU3RvcmUgU2F2aW5ncw==?=
To: 		dortmann31415@yahoo.com
MIME-Version: 		1.0
Content-Type: 		multipart/alternative; boundary="ABCD-W0TH05302446C012CCC782EDD0DA30-EFGH"
Content-Length: 		23933 

I subscribe to yahoo's business email and download email with pop3.  My wife does not have email header corruption problems using Thunderbird.  I *do* have problems using kmail.  The problems have become much more frequent in the past month or two.

These are the headers that I see after pop3 email download:

From unknown@unknown.invalid Thu Nov 27 18:30:34 2008
X-Apparently-To: dortmann31415@yahoo.com via 206.190.39.240; Thu, 27 Nov 2008 13:33:56 -0800
X-YMailISG: 1TGV5X4tYB1nadsS65GHN8gbADDwasqHM_zHsh71iQg7bf4zMW7gJySaJfCrgduRm6xJ7Z01Rg2DagBIqSQ_oloAMq5CDS3b9mbCEbBsrvZgi0kvpQwzlBK4HpIvE6z7tMoFH1Fx96.vHh7fRuhGwaxwSyFQ1Qd9sWZT5vAwSK9BYPtuRnSADSx_i2b_UubkqvRINRfZlijJOzDkmty34ufEScUmTlg-
X-Originating-IP: [72.5.68.133]
Authentication-Results: mta271.mail.mud.yahoo.com  from=newsletters.walmart.com; domainkeys=pass (ok)
Status: R
X-Status: NC
X-KMail-EncryptionState:  
X-KMail-SignatureState:  
X-KMail-MDN-Sent:  

; from=newsletters.walmart.com; dkim=neutral  (no  sig)
Received: from 72.5.68.133  (HELO mx-v11.gm.mail.yahoo.com) (72.5.68.133)
  by mta271.mail.mud.yahoo.com with SMTP; Thu, 27 Nov 2008 13:33:56 -0800
Transit-DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws;
  s=transit_gm2; d=yahoo.goodmailsystems.com;
  h=X-Originating-IP:X-YahooSRV:X-GoodmailSystems-Canceled:Received:X-GoodmailSystems:X-GoodmailSystems-Rcpto:X-GoodmailSystems-Cert:X-GoodmailSystems-Entity:X-GoodmailSystems-Sig:DomainKey-Signature:X-Habeas-Report:Reply-To:Bounces_to:Message-ID:X-BFI:Date:From:Subject:To:MIME-Version:Content-Type;
  b=dZOcRi3j5CK61uMZmoSOJYczPLLvSED2TwnpaRtpMxnqPoEz5kasI9O2OXPlT+++HPfiWZemd1SjCOgHFXYYHTAInjuoDGRcMk/g6CevUiFvrB6R9ygn2TGeGtSDs0aaETJ4udtbzYDXco2Ziy2Pkl1qAweCAfuYh/+t5JpGz04=  ;
X-Originating-IP: [206.132.3.226]
X-YahooSRV: GMSEntity="Wal-Mart"
X-GoodmailSystems-Canceled: 2; h=ycgw47.sjc.mta.yahoo.com; d=20081127T213343; m=2930; p=4
Received: from arm226.bigfootinteractive.com (HELO bigfootinteractive.com) (206.132.3.226)
  by ycgw47.sjc.mta.yahoo.com with SMTP; 27 Nov 2008 21:33:43 -0000
X-GoodmailSystems: 2; i="1"; 
	s="000063020000630200000001492F11E26F09044E000511920000001200000001"; 
	e="20081130T213218"; d="20081127T213218"; o="15243"; t="0"; p="4"; 
	h="SERgz3WQDAl86Yv/0Saf6YdaiNo="; b="3DyZmW2fUJRdn4njJsGajPEMO7k="; 
	f="PT9pc28tODg1OS0xP0I/VjJGc2JXRnlkQ0JYYVhKbD89IDx3YWxtYXJ0QG5ld3NsZXR0ZXJzLndhb
	G1hcnQuY29tPg=="; I="001002000";
X-GoodmailSystems-Rcpto: dortmann31415@yahoo.com
X-GoodmailSystems-Cert: MIICeTCCAWECBBAAAC8wDQYJKoZIhvcNAQEFBQAwIDEeMBwGA1UEAxM
	VU0NBOlgtR29vZG1haWxTeXN0ZW1zMB4XDTA4MTEwMTAwMDAwMFoXDTA5MDgwMTAwMDAwMFowgYkxCzA
	JBgNVBAYTAlVTMQswCQYDVQQIEwJDQTEWMBQGA1UEBxMNTW91bnRhaW4gVmlldzERMA8GA1UEChMIR29
	vZG1haWwxDDAKBgNVBAsTA09wczEMMAoGA1UEAxMDT3BzMSYwJAYJKoZIhvcNAQkBFhdvcHNAZ29vZG1
	haWxzeXN0ZW1zLmNvbTB8MA0GCSqGSIb3DQEBAQUAA2sAMGgCYQC3887/bsJFUMJOuV9VXge1q0sxeak
	Mv9FsR+hdbWrCXW/VxADMCZ9sneXD65aSwiudwudxUue+2Iq7Sa9Jp0grv8p5ghR/+0j878w9bTrEovt
	SA+UwVb0K0JLzRtVG0HECAwEAATANBgkqhkiG9w0BAQUFAAOCAQEAVip+7RsAot+UuRznv13MwSr6lV+
	Nggm/1Jj7+aBV3lswaeterJV+dy1DTG50ix+rKfcCCfH3uR6CbrxXn/ZSx+YLacOpAoUuA2pAmnSxSGM
	8KS254fQ6VTSXC4MWQ8Ei48IRNMQEbdGkCXu9q+4Ktdy1lnNwfXz9cT71i9EcAzJERJW8qNovor8TCT4
	yEUAOO4u4OdKBnYSdy4+iSS/njpNehJS0koCOe6Twnfros+DL856KTNffKN0GZmXsZhBZvf8o3JModp9
	8pWSY4lct/8TR1T6fBDTW1q1xx04OcDQSjq3gb5PbSbwl62wmmN6O2MZEfwxl0XSWxg9h5Dp7VA==
X-GoodmailSystems-Entity: Wal-Mart
X-GoodmailSystems-Sig: irYCjXatoDkwYY9etN85hg0Q6kWANVMe2m6ifxSU29m5a6rX5uHMgFaz
	c5x5UHNxZwem7AYwJ43xHq6YsDdUtJUovtEaPI9OmdyA3omtBorYfiNEsjtYdBRYfSr0IyyJ
DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws;
   s=bfi; d=newsletters.walmart.com;
   b=g2/uZOw19JuAeWQXiC7Z1jGcD603bAIKhNydV6WnI2utsiDlhiYVNB3X9IL9mhqw;
X-Habeas-Report: Please report use of this mark in spam to http://www.habeas.com/report/
Reply-To: walmart.W0TH05302446C012CCC782EDD0DA30@newsletters.walmart.com
Bounces_to: walmart@newsletters.walmart.com
Message-ID: <W0TH05302446C012CCC782EDD0DA30.6849.7747.pimailer52.DumpShot.1@newsletters.walmart.com>
X-BFI: W0TH05302446C012CCC782EDD0DA30
Date: Thu, 27 Nov 2008 16:32:17 EST
From: =?iso-8859-1?B?V2FsbWFydCBXaXJl?= <walmart@newsletters.walmart.com>
Subject: =?iso-8859-1?B?VGhhbmtzZ2l2aW5nIERheSBTcGVjaWFscyArIERvbid0IE1pc3MgRnJpZGF5J3MgSW4tU3RvcmUgU2F2aW5ncw==?= 
To: dortmann31415@yahoo.com
MIME-Version: 1.0
Content-Type: multipart/alternative;
   boundary="ABCD-W0TH05302446C012CCC782EDD0DA30-EFGH"

--ABCD-W0TH05302446C012CCC782EDD0DA30-EFGH
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: quoted-printable

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Thanksgiving Day Online Specials
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Note the problem (wrapping?) occurs repeatedly at the semicolon on the Authentication-Results line at about column 110.