Hi Chris, I’m working with cruelmelody on this issue.
I was able to fix the issue by un-ticking this option in wpMandrill settings:
Replace all line feeds ("\n") by <br/> in the message body?
The downside is that plain-text emails don’t have proper line breaks anymore, but we’ll be able to solve that by applying the filters selectively.
I’ll ask cruelmelody to mark this as “resolved”.
Thanks for your assistance!