Looks like NEWS.md does need to be ignored.

dtkaplan · dtkaplan · commit cb4af1f75b7f · 2017-09-19T14:28:23.000-04:00
diff --git a/.Rbuildignore b/.Rbuildignore
@@ -4,4 +4,5 @@ cran-comments.md
 ^README\.Rmd$
 ^README\.md$
 ^README-.*\.png$
+^NEWS\.md$
 ^\.travis\.yml$
