--- MMagic.pm
+++ MMagic.pm
@@ -929,7 +929,7 @@ sub magicMatch {
 	}
 	else {
 #	    $$p_desc .= ' ' . sprintf($message,$data) if $message;
-	    $$p_desc .= sprintf($message,$data) if $message;
+	    $$p_desc .= index($message, '%') >= 0 ? sprintf($message, $data) : $message if $message;
 	}
 
 	my $subtest;
@@ -1094,7 +1094,7 @@ sub magicMatchStr {
 	}
 	else {
 #	    $$p_desc .= ' ' . sprintf($message,$data) if $message;
-	    $$p_desc .= sprintf($message,$data) if $message;
+	    $$p_desc .= index($message, '%') >= 0 ? sprintf($message, $data) : $message if $message;
 	}
 
 	my $subtest;