[Private Messaging] Line and paragraph breaks not working

Hi! I have your Private Messaging plugin running on my Multisite staging environment, and it's all working okay except for the fact that line breaks don't carry over to the received message. Basically, even though I do line and paragraph breaks in the compose/reply modal, the recipient just sees all of the text smooshed together into one paragraph. I'd like my recipients to be able to see the line breaks as entered, without needing to enable the WYSIWYG editor. Please help! Thank you!