Header DATE field not returned when placed after MIME section

[Xavier Guerin]

Hello,

I am using Dovecot 2.2.34p0 on OpenBSD 6.3 stable.

I am writting an application using the vmime (http://www.vmime.org)
library (x-ref issue: https://github.com/kisli/vmime/issues/199).

I noticed through testing over my own e-mail server that in some
situations the DATE field is not returned upon ENVELOPE or
HEADER.FIELDS request.

The e-mails at fault happen to have the DATE field at the very end of
the header, after the MIME section.

Example 1:

Delivered-To: 
Received: 
Return-Path:
Delivered-To: 
DKIM-Signature: 
From: 
To: 
Message-ID:
Subject:
MIME-Version: 1.0
Content-Type: text/html;charset=UTF-8
Content-Transfer-Encoding: 7bit
Date: Fri, 01 Jun 2018 17:44:44 -0400

Example 2:

Return-Path:
Delivered-To: 
Received: 
Delivered-To:
DKIM-Signature:
From: 
Reply-To: 
To: 
Subject: 
MIME-Version: 1.0
Content-Type: multipart/mixed; 
        boundary="----=_Part_338_1573405959.1527768044781"
X-Mailer: EMail_2.0
Date: Fri, 01 Jun 2018 17:36:01 -0400

Thanks in advance for the insight,