Index: wp-includes/default-widgets.php
===================================================================
--- wp-includes/default-widgets.php	(revision 22252)
+++ wp-includes/default-widgets.php	(working copy)
@@ -857,18 +857,18 @@
 			$title = __('Untitled');
 
 		$desc = str_replace( array("\n", "\r"), ' ', esc_attr( strip_tags( @html_entity_decode( $item->get_description(), ENT_QUOTES, get_option('blog_charset') ) ) ) );
-		$desc = wp_html_excerpt( $desc, 360 );
+		$excerpt = wp_html_excerpt( $desc, 360 );
 
 		// Append ellipsis. Change existing [...] to […].
-		if ( '[...]' == substr( $desc, -5 ) )
-			$desc = substr( $desc, 0, -5 ) . '[…]';
-		elseif ( '[…]' != substr( $desc, -10 ) )
-			$desc .= ' […]';
+		if ( '[...]' == substr( $excerpt, -5 ) )
+			$excerpt = substr( $excerpt, 0, -5 ) . '[…]';
+		elseif ( '[…]' != substr( $excerpt, -10 ) && $desc != $excerpt )
+			$excerpt .= ' […]';
 
-		$desc = esc_html( $desc );
+		$excerpt = esc_html( $excerpt );
 
 		if ( $show_summary ) {
-			$summary = "<div class='rssSummary'>$desc</div>";
+			$summary = "<div class='rssSummary'>$excerpt</div>";
 		} else {
 			$summary = '';
 		}