email formatting - line feeds/breaks not retained

[atomGit]

doesn't matter how i edit the template for post notification emails (visual or text editor) or how many line breaks i add between sentences, when i receive post notifications, all vertical space/line feeds are removed from the email body

WP 5.2.4
Post Notification by Email 4.1.3
email client: Thunderbird (display format (html, text) doesn't matter)