Steps to reproduce:

1. Go to WP Admin > Settings > Reading, select "Summary" for feeds, and Save Changes
2. Start a new post at https://wordpress.com/post
3. Add a poem to the body of the post
4. Save and publish
5. View the post in the Reader stream it https://wordpress.com/

Result: line breaks are not displayed for excerpts in summary feeds. This causes a problem for poetry formatting.

^{Seen at https://wordpress.com/ on this blog https://wordpress.com/read/blog/feed/40471243 for this post https://wordpress.com/read/post/feed/40471243/872344084 using Firefox 42.0 on Mac OS X 10.10.5}

Sample content:

why did you go
little fourpaws?
you forgot to shut
your big eyes.

where did you go?
like little kittens

e e cummings

/hat tip alexjgustafson for the original report