diff --git a/u_parrots.go b/u_parrots.go
index 1b82ff8..b744ee8 100644
--- a/u_parrots.go
+++ b/u_parrots.go
@@ -513,7 +513,8 @@ func (uconn *UConn) generateRandomizedSpec() (ClientHelloSpec, error) {
 	if r.FlipWeightedCoin(0.4) {
 		p.TLSVersMin = VersionTLS10
 		p.TLSVersMax = VersionTLS13
-		tls13ciphers := defaultCipherSuitesTLS13()
+		tls13ciphers := make([]uint16, len(defaultCipherSuitesTLS13()))
+		copy(tls13ciphers, defaultCipherSuitesTLS13())
 		r.rand.Shuffle(len(tls13ciphers), func(i, j int) {
 			tls13ciphers[i], tls13ciphers[j] = tls13ciphers[j], tls13ciphers[i]
 		})