Header encoding after export email to EML format (RFC822)

Question

We are using Redemption (v5.26) to convert messages from .msg format to .eml format in an Outlook COM addin.

I have created an email with the following subject: ÁRVÍZTŰRŐ TÜKÖRFÚRÓGÉP and copied the subject to the message body. I've sent the message and after I received the message I made my test to check one of out customers report.

Our code does the following:

• saves the current email to a .msg file using the following method _mailItem is the Outlook native MailItem:

_mailItem.SaveAs(filename, OlSaveAsType.olMSG);

• converts the .msg file to .eml using Redemption (the objects are released of course)

rdoSession = RedemptionLoader.new_RDOSession();
rdoMail = rdoSession.GetMessageFromMsgFile(input);
rdoMail.SaveAs(output, rdoSaveAsType.olRFC822_Redemption);

Then checked the generated file and this is what it represented: the subject encoded like below:

Subject: =?iso-8859-2?B?wVJWzVpUVVJPIFTcS9ZSRtpS00fJUA==?=

which is ÁRVÍZTURO TÜKÖRFÚRÓGÉP encoded.

The message body is encoded like below:

--7A24CA1FB85D3A4CB677EFC32587A338-474D54B8_message_boundary
Content-type: text/plain; charset=iso-8859-2
Content-Transfer-Encoding: Base64
Content-Disposition: inline
Content-Description: Message text

wVJWzVpU21LVIFTcS9ZSRtpS00fJUA0K
--7A24CA1FB85D3A4CB677EFC32587A338-474D54B8_message_boundary

which is encoded correctly.

Our customer reported it the same behavior but in the To and From headers.

Can I do anything to fix these fields encoding or is this a bug?