check that subreddit_about exists (sometimes it might be null and referencing to the public_description_html will throw an error

views/subreddit.pug

@@ -3,7 +3,8 @@ html
   head
     title /r/#{subreddit}
     meta(property='og:title', content='/r/' + subreddit)
-    meta(property='og:description', content='' + unescape(subreddit_about.public_description_html, user_preferences))
+    if subreddit_about
+      meta(property='og:description', content='' + unescape(subreddit_about.public_description_html, user_preferences))
     include includes/meta_default.pug
     include includes/head.pug
   body(class=""+ (user_preferences.theme === 'auto' ? 'dark' : user_preferences.theme) + "")