Duplicate Welcome Email Body Content

Just completed a fresh install with version 3.10.4 and received the following email:

This is a multi-part message in MIME format.

--b1_70b2b698877c2f18b805bfbda5cd2679
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit

Hi my website,<br/><br/>Your Osclass Enterprise installation at mywebsite.com is up and running. You can access the administration panel with these details:<br/><ul><li>username: my username</li><li>password: my password</li></ul>Remember that for any doubts you might have you can consult our <a href="https://docs.enterprise-classifieds.com/">documentation</a>, <a href="https://www.valueweb.gr/forums/enterprise-release/">forum</a> or <a href="https://enterprise-classifieds.com/blog/">blog</a>. Osclass doesn’t run any developments but we can put you in touch with third party developers through a Premium Support. And hey, if you would like to contribute to Osclass - learn how <a href="https://www.valueweb.gr/forums/enterprise-release/">here</a>!<br/><br/>Cheers,<br/>The <a href="https://www.valueweb.gr/forums/enterprise-release/">Osclass Enterprise</a> team

--b1_70b2b698877c2f18b805bfbda5cd2679
Content-Type: text/html; charset=utf-8
Content-Transfer-Encoding: 8bit

Hi my website,<br/><br/>Your Osclass Enterprise installation at mywebsite.com is up and running. You can access the administration panel with these details:<br/><ul><li>username: my username</li><li>password: my password</li></ul>Remember that for any doubts you might have you can consult our <a href="https://docs.enterprise-classifieds.com/">documentation</a>, <a href="https://www.valueweb.gr/forums/enterprise-release/">forum</a> or <a href="https://enterprise-classifieds.com/blog/">blog</a>. Osclass doesn’t run any developments but we can put you in touch with third party developers through a Premium Support. And hey, if you would like to contribute to Osclass - learn how <a href="https://www.valueweb.gr/forums/enterprise-release/">here</a>!<br/><br/>Cheers,<br/>The <a href="https://www.valueweb.gr/forums/enterprise-release/">Osclass Enterprise</a> team

--b1_70b2b698877c2f18b805bfbda5cd2679--

I replaced the personal info for security reasons of course.  I am wondering why I am receiving duplicate body content with html tags (mime format) instead of html.  I use Thunderbird and it is set to show emails in html format. Looked through the email templates and cannot see any with duplicate welcome content in the body of the email.  Any ideas?