Hello,
We purposely remove the line break in the showcase module in order to minimize the content displayed inside the showcase. If you want to truncate the blog intro text with the line break for the showcase module you can download my attachment below and place it inside your /components/com_easyblog/themes/default folder.
Be warned that it might messed up some of the styling layout inside the showcase content and we will not help you to optimize the styling for this customization. Hope you understand