There's a fix for it. Add another mail account in Pocket Outlook and set it to check for messages manually (it can even be a dummy account if you don't have another email account that you want to add). Once you do that, whatever account you last had open is the one that it will open to when you tap on the email icon. For some reason, having just the MMS account and your email account isn't good enough - you need to have a 3rd account in there for it to work properly. Let me know if you have any questions.