client.go | 2 +-

diff --git a/client.go b/client.go
index 36f840fac95f81aa159dd54ea947fb7c6fc9cc45..d2ebfbcd71500747cc568ed3c3849ce12de23e7b 100644
--- a/client.go
+++ b/client.go
@@ -1277,7 +1277,7 @@ }
 
 func copyTrackers(base [][]tracker.Client) (copy [][]tracker.Client) {
 	for _, tier := range base {
-		copy = append(copy, tier)
+		copy = append(copy, append([]tracker.Client{}, tier...))
 	}
 	return
 }