This is the original message in my Outlook "Sent Items" (I use Outlook 2016 With OVH Hosted Exchange):

Hey Gabriele, if you can IM me the raw text of the email I can debug the issue for you.

I was able to replicate the same issue with the raw text you provided.  I've created a bug report for it.  Thanks.

Hey Gabriele, I took this message and sent it to my Exchange server to see what would happen and it is also displaying it incorrectly.  Like you reported it does show up correct in webmail though.  Can you create a new temporary folder, start up Fiddler, move the email into that folder, click 'Update Folder' in Outlook, then send me that fiddler trace.  You can move the email back once this is done.

I'll want to compare my Fiddler trace with yours to see if we're missing something.  Thanks!

Unfortunately (or perhaps fortunately) these days I am full of work and I don't have much time to devote to debugging SM ...

Sorry Larry, maybe next week or so on...

Sounds good, thanks.  Since my local Exchange server also displays the signature cutoff then there will not be any other debugging I can do on my end without that Fiddler trace.

I can send you an email from my account in my Exchange server (actually it's the account that I used to send the original message to SM) and we can see if it come to you cutted of...

At what email address can i send it?

Hey Gabriele, it looks like the one you sent me from the OVH hosted exchange came in with the signature cutoff but the ones you replied to from Gmail and Outlook.com look correct.  I'll see what the differences are between the different versions of the message.

Looking at this further and it appears to not be a MAPI bug.  The image that was appearing cutoff was wrapped in this tag:

<p class="MsoNormal" style="line-height:8.0pt;mso-line-height-rule:exactly;">

So Outlook was only showing 8 pixels of the image.

Mmmmh, interesting! So it seems that it's Outlook that does something wrong. GMAIL and OUTLOOK.COM seem to be smart enough to correct this issue on the fly, while Outlook and Exchange are not...

A really Microsoft way of work! ;-)

Ok, I will try to look at the sign in my Outlook to understand why it envelope the image like that...