Darn it, it's the more_news page's header that's adding those. I'll get that corrected, too.
Open /includes/modules/pages/more_news/header.php.php and find
Code:
$news_title = nl2br($news_box_query->fields['news_title']);
$news_content = nl2br($news_box_query->fields['news_content']);
Change those lines, removing the call to nl2br (which converts any new-line characters to <br />'s):
Code:
$news_title = $news_box_query->fields['news_title'];
$news_content = $news_box_query->fields['news_content'];
I'll get that logged and updated on the plugin's GitHub repository.
Update: https://github.com/lat9/news_box_manager/issues/8