diff --git a/internal/contracts/manager.go b/internal/contracts/manager.go
index 1dc327102..122f07243 100644
--- a/internal/contracts/manager.go
+++ b/internal/contracts/manager.go
@@ -857,11 +857,14 @@ func (cm *contractManager) AddContractListener(ctx context.Context, listener *co
 		}
 
 		// Namespace + Topic + Location + Signature must be unique
+		if len(strings.TrimSpace(listener.Location.String())) == 0 {
+			listener.Location = nil // consistently store nil
+		}
 		listener.Signature = cm.blockchain.GenerateEventSignature(ctx, &listener.Event.FFIEventDefinition)
 		fb := database.ContractListenerQueryFactory.NewFilter(ctx)
 		if existing, _, err := cm.database.GetContractListeners(ctx, cm.namespace, fb.And(
 			fb.Eq("topic", listener.Topic),
-			fb.Eq("location", listener.Location),
+			fb.Eq("location", listener.Location), // we query nil
 			fb.Eq("signature", listener.Signature),
 		)); err != nil {
 			return err
diff --git a/internal/contracts/manager_test.go b/internal/contracts/manager_test.go
index 2663cecdd..726ada3d8 100644
--- a/internal/contracts/manager_test.go
+++ b/internal/contracts/manager_test.go
@@ -788,6 +788,47 @@ func TestAddContractListenerInline(t *testing.T) {
 	mdi.AssertExpectations(t)
 }
 
+func TestAddContractListenerInlineEmptyString(t *testing.T) {
+	cm := newTestContractManager()
+	mbi := cm.blockchain.(*blockchainmocks.Plugin)
+	mdi := cm.database.(*databasemocks.Plugin)
+
+	sub := &core.ContractListenerInput{
+		ContractListener: core.ContractListener{
+			Location: fftypes.JSONAnyPtr("   "),
+			Event: &core.FFISerializedEvent{
+				FFIEventDefinition: fftypes.FFIEventDefinition{
+					Name: "changed",
+					Params: fftypes.FFIParams{
+						{
+							Name:   "value",
+							Schema: fftypes.JSONAnyPtr(`{"type": "integer"}`),
+						},
+					},
+				},
+			},
+			Options: &core.ContractListenerOptions{},
+			Topic:   "test-topic",
+		},
+	}
+
+	mbi.On("NormalizeContractLocation", context.Background(), blockchain.NormalizeListener, sub.Location).Return(sub.Location, nil)
+	mbi.On("GenerateEventSignature", context.Background(), mock.Anything).Return("changed")
+	mdi.On("GetContractListeners", context.Background(), "ns1", mock.Anything).Return(nil, nil, nil)
+	mbi.On("AddContractListener", context.Background(), mock.MatchedBy(func(cl *core.ContractListener) bool {
+		return cl.Location == nil // converted from empty string
+	})).Return(nil)
+	mdi.On("InsertContractListener", context.Background(), &sub.ContractListener).Return(nil)
+
+	result, err := cm.AddContractListener(context.Background(), sub)
+	assert.NoError(t, err)
+	assert.NotNil(t, result.ID)
+	assert.NotNil(t, result.Event)
+
+	mbi.AssertExpectations(t)
+	mdi.AssertExpectations(t)
+}
+
 func TestAddContractListenerNoLocationOK(t *testing.T) {
 	cm := newTestContractManager()
 	mbi := cm.blockchain.(*blockchainmocks.Plugin)