Email Signature not populating when attaching a document

I am running into an issue where my email signature won’t show up if I try to share a document from a matter via email.  It will show up when I select a contacts email from the preview at the right.  So I’m wondering if there is an Outlook integration issue.  To further clarify, from the matter documents, I right click on an attachment and select Send, then Email.  I select multiple recipients, click Next, then a blank email with the attachment and recipients will pop up.  No email signature.  It’s a minor issue, but some users in our office can’t easily navigate Outlook.