diff --git a/wp-includes/capabilities.php b/wp-includes/capabilities.php
index 70d651ff5..0c95173e4 100644
--- a/wp-includes/capabilities.php
+++ b/wp-includes/capabilities.php
@@ -831,11 +831,10 @@ function map_meta_cap( $cap, $user_id ) {
 			break;
 		}
 
-		if ( '' != $post->post_author && post_type_supports( $post_type->name, 'author' ) ) {
+		if ( '' != $post->post_author ) {
 			$post_author_data = get_userdata( $post->post_author );
 		} else {
-			// No author set yet or post type doesn't support authors,
-			// so default to current user for cap checks.
+			// No author set yet, so default to current user for cap checks.
 			$post_author_data = $author_data;
 		}
 
@@ -874,11 +873,10 @@ function map_meta_cap( $cap, $user_id ) {
 			break;
 		}
 
-		if ( '' != $post->post_author && post_type_supports( $post_type->name, 'author' ) ) {
+		if ( '' != $post->post_author ) {
 			$post_author_data = get_userdata( $post->post_author );
 		} else {
-			// No author set yet or post type doesn't support authors,
-			// so default to current user for cap checks.
+			// No author set yet, so default to current user for cap checks.
 			$post_author_data = $author_data;
 		}
 
@@ -921,11 +919,10 @@ function map_meta_cap( $cap, $user_id ) {
 			break;
 		}
 
-		if ( '' != $post->post_author && post_type_supports( $post_type->name, 'author' ) ) {
+		if ( '' != $post->post_author ) {
 			$post_author_data = get_userdata( $post->post_author );
 		} else {
-			// No author set yet or post type doesn't support authors,
-			// so default to current user for cap checks.
+			// No author set yet, so default to current user for cap checks.
 			$post_author_data = $author_data;
 		}
 
diff --git a/wp-includes/post.php b/wp-includes/post.php
index 1098ede9d..8785b69b3 100644
--- a/wp-includes/post.php
+++ b/wp-includes/post.php
@@ -1086,7 +1086,8 @@ function get_post_type_capabilities( $args ) {
 	}
 
 	if ( ! post_type_supports( $args->name, 'author' ) ) {
-		// While these may be checked in core, users/roles shouldn't need to be granted these.
+		// While these may be checked in core, users/roles shouldn't need to be
+		// granted these by default if the post type doesn't support authors.
 		$default_capabilities['edit_others_posts']   = $default_capabilities['edit_posts'];
 		if ( $args->map_meta_cap )
 			$default_capabilities['delete_others_posts'] = $default_capabilities['delete_posts'];