diff --git a/imperative/src/impl/interpreter/interpreter_impl.cpp b/imperative/src/impl/interpreter/interpreter_impl.cpp
index 1c11b9370b2570b7191247c6b5dd707b70c86c88..dac2726de97a59766b5363e5de569af0f56340bd 100644
--- a/imperative/src/impl/interpreter/interpreter_impl.cpp
+++ b/imperative/src/impl/interpreter/interpreter_impl.cpp
@@ -855,6 +855,9 @@ void ChannelImpl::do_apply_op(const ApplyOp& cmd, std::string reason) {
     } else {
         // i may be null
         validated = false;
+        for (auto i : cmd.outputs) {
+            output_descs.push_back({});
+        }
     }
     // Here std::move is REQUIRED for removing duplicated references.
     auto outputs = apply_on_physical_tensor(
diff --git a/imperative/src/impl/ops/concatenate.cpp b/imperative/src/impl/ops/concatenate.cpp
index a6a9c3a7122b6d44832be50cc2772a1e7c816f54..cf0e34d7a1d7f0dcde2c2832d6d21b11f32e8a90 100644
--- a/imperative/src/impl/ops/concatenate.cpp
+++ b/imperative/src/impl/ops/concatenate.cpp
@@ -111,13 +111,14 @@ SmallVector<TensorPtr> apply_on_physical_tensor(
     int axis = op_def.axis >= 0 ? op_def.axis : op_def.axis + inputs[0]->layout().ndim;
 
     CompNode& oup_cn = output_descs[0].comp_node;
-    if (op_def.comp_node.valid()) {
-        mgb_assert(op_def.comp_node == oup_cn, "Concat compnode infer error");
-    }
-
-    // prepare inputs and output layout
     TensorLayout& oup_layout = output_descs[0].layout;
-    if (!validated) {
+    if (validated) {
+        if (op_def.comp_node.valid()) {
+            mgb_assert(op_def.comp_node == oup_cn, "Concat compnode infer error");
+        }
+    } else {
+        // prepare inputs and output layout
+        oup_cn = inputs[0]->comp_node();
         SmallVector<const TensorLayout*> inputs_holder(inputs.size());
         for (size_t i = 0; i < inputs.size(); ++i) {
             inputs_holder[i] = &inputs[i]->layout();
@@ -213,13 +214,14 @@ SmallVector<TensorPtr> apply_on_physical_tensor(
             op_def.axis >= 0 ? op_def.axis : op_def.axis + inputs[0]->layout().ndim + 1;
 
     CompNode& oup_cn = output_descs[0].comp_node;
-    if (op_def.comp_node.valid()) {
-        mgb_assert(op_def.comp_node == oup_cn, "Stack compnode infer error");
-    }
-
-    // prepare inputs and output layout
     TensorLayout& oup_layout = output_descs[0].layout;
-    if (!validated) {
+    if (validated) {
+        if (op_def.comp_node.valid()) {
+            mgb_assert(op_def.comp_node == oup_cn, "Stack compnode infer error");
+        }
+    } else {
+        // prepare inputs and output layout
+        oup_cn = inputs[0]->comp_node();
         SmallVector<const TensorLayout*> inputs_holder(inputs.size());
         for (size_t i = 0; i < nr_inp; ++i) {
             inputs_holder[i] = &inputs[i]->layout();