Hello @mrtheable thanks for your post. When you are creating an email campaign try this...
click on the footer area at the bottom of the email creation screen. Under the options for Twitter, see if there is anything listed. It may appear blank, but just to be sure highlight that field in the editable text field area, and click delete with your keyboard. It's possible there is a space or other hidden character that is keeping the logo to appear in your footer.
You can also view a past or a sample email and hover over the Twitter logo, just to see if a distinct URL pops up. This could give you a clue if there is something listed for your Twitter, eventhough you don't have one or see it in your email creation area. Hope this helps answer your question.
