diff --git a/builder/backend.go b/builder/backend.go
index d014a7efb2..77fdbc2b31 100644
--- a/builder/backend.go
+++ b/builder/backend.go
@@ -182,7 +182,12 @@ func (b *Backend) handleRegisterValidator(w http.ResponseWriter, req *http.Reque
 	for _, registerRequest := range payload {
 		pubkeyHex := PubkeyHex(registerRequest.Message.Pubkey.String())
 		if previousValidatorData, ok := b.validators[pubkeyHex]; ok {
-			if registerRequest.Message.Timestamp <= previousValidatorData.Timestamp {
+			if registerRequest.Message.Timestamp < previousValidatorData.Timestamp {
+				respondError(w, http.StatusBadRequest, "invalid timestamp")
+				return
+			}
+
+			if registerRequest.Message.Timestamp == previousValidatorData.Timestamp && (registerRequest.Message.FeeRecipient != previousValidatorData.FeeRecipient || registerRequest.Message.GasLimit != previousValidatorData.GasLimit) {
 				respondError(w, http.StatusBadRequest, "invalid timestamp")
 				return
 			}
diff --git a/builder/backend_test.go b/builder/backend_test.go
index 1158d06f25..762903f923 100644
--- a/builder/backend_test.go
+++ b/builder/backend_test.go
@@ -64,8 +64,7 @@ func TestValidatorRegistration(t *testing.T) {
 	require.Equal(t, ValidatorData{FeeRecipient: payload[0].Message.FeeRecipient, GasLimit: payload[0].Message.GasLimit, Timestamp: payload[0].Message.Timestamp}, backend.validators[PubkeyHex(v.Pk.String())])
 
 	rr = testRequest(t, backend, "POST", "/eth/v1/builder/validators", payload)
-	require.Equal(t, http.StatusBadRequest, rr.Code)
-	require.Equal(t, `{"code":400,"message":"invalid timestamp"}`+"\n", rr.Body.String())
+	require.Equal(t, http.StatusOK, rr.Code)
 
 	payload[0].Message.Timestamp += 1
 	// Invalid signature