SMTP boundary for voice mail not working as expected

The LR 9.52 SMTP capture puts a multi-part/mixed voice mail message into a parameter. However, a replay creates an Outlook "message" but no voice mail is attached. Added the "Boundary". From the pcap capture, it doesn't appear that the "Boundary:" directive is being interpreted as entered.
Call:
smtp_send_mail_ex(&ppsmtp, "SendMail",
"From=<53060@mmlab2mss01lnx.fmr.com> AUTH=53060@mmlab2mss01lnx.fmr.com",
"To=53044@mmlab2mss01lnx.fmr.com",
"Subject=SMTP Create Msg from Script",
"ContentType=Multipart/Mixed;",
MAILOPTIONS,
"To: \"McCarthy, Kevin\" <53044@mmlab2mss01lnx.fmr.com>",
"From: <53060@mmlab2mss01lnx.fmr.com> \"Bond, James\"",
"X-Priority:3",
"Importance:Normal",
"Sensitivity:Normal",
"Content-Type:multipart/mixed;",
"Mailer: XYZ Messaging Client",
"X-Mailer: XYZ Messaging Client",
"Message-Context:voice-message",
"MIME-Version: 1.0",
"Boundary:--Mark=_2935880420_20091271955483846xiKGE--",
MAILDATA, param16_1, LAST);

Begining of param1 is (long voicemail):
const char* param16_1=
"MessageText=This is a multi-part message in MIME format."
"\r\n\r\n\r\n--Mark=_2935880420_20091271955483846xiKGE\r\nContent-Type:"
" text/Plain; charset=iso-8859-1\r\nContent-Transfer-Encoding: "
"Quoted-Printable\r\n\r\n\r\n\r\n--Mark="
"_2935880420_20091271955483846xiKGE\r\nContent-Type: audio/wav;\r\n\t"
"name=\"MM1DF.wav\";\r\n\tcharset=\"US-ASCII\"\r\n"
"Content-Transfer-Encoding: BASE64\r\n\r\n"
"UklGRtqLAABXQVZFZm10IBQAAAAxAAEAQB8AAFkGAABBAAAAAgBAAWZhY3QEAAAAgK8CAG"
"RhdGGm\r\niwAA4tfchYCCAJPWTeMYy0CjO3Pd1 "
"pglrdxEy2sYNlI9vXKZYnZLPUMaHPU3FrUDMRRNSCx0woi\r\n"
...
"\r\n--Mark=_2935880420_20091271955483846xiKGE\r\n"

pcap captures shows:
Subject=SMTP Create Msg from Script\r\n
MIME-Version: 1.0\r\n
Content-Type:multipart/mixed;\r\n
\tboundary="------=_NextPart_00000001_00001264.00f2c388"\r\n
To="McCarthy,Kevin" <53044@mmlab2mss01lnx.fmr.com\r\n
X-Priority:3\r\n
Importance:Normal\r\n
Message-Context:voice-message\r\n
Sensitivity:Normal\r\n
Mailer: XYZ Messaging Client\r\n
X-Mailer: XYZ Messaging Client\r\n
\r\n
This is a multipart message in MIME format.\r\n
---------------NextPart_00000001_00001264.00f2c388\r\n
This is a multi-part message in MIME format.\r\n
\r\n\r\n\r\n--Mark=_2935880420_20091271955483846xiKGE\r\nContent-Type:
text/Plain; charset=iso-8859-1\r\nContent-Transfer-Encoding:
Quoted-Printable\r\n\r\n\r\n\r\n
--Mark=_2935880420_20091271955483846xiKGE\r\nContent-Type: audio/wav;\r\n\t
name=\"MM1DF.wav\";\r\n\tcharset=\"US-ASCII\"\r\n"
Content-Transfer-Encoding: BASE64\r\n\r\n
UklGRtqLAABXQVZFZm10IBQAAAAxAAEAQB8AAFkGAABBAAAAAgBAAWZhY3QEAAAAgK8CAG
...
---------------NextPart_00000001_00001264.00f2c388\r\n