diff --git a/pkg/vm/vm.go b/pkg/vm/vm.go
index a3c14149d..c9bc97d2b 100644
--- a/pkg/vm/vm.go
+++ b/pkg/vm/vm.go
@@ -641,9 +641,6 @@ func (v *VM) execute(ctx *Context, op Instruction) {
 			arr := t.Value().([]StackItem)
 			arr = append(arr, itemElem.value)
 			t.value = arr
-		case *ByteArrayItem:
-			newVal := append(t.value, itemElem.value.Value().([]byte)...)
-			v.estack.PushVal(newVal)
 		default:
 			panic("APPEND: not of underlying type Array")
 		}
diff --git a/pkg/vm/vm_test.go b/pkg/vm/vm_test.go
index 1a7b466b4..5a7f5771a 100644
--- a/pkg/vm/vm_test.go
+++ b/pkg/vm/vm_test.go
@@ -479,6 +479,15 @@ func TestAPPENDBad1Argument(t *testing.T) {
 	assert.Equal(t, true, vm.state.HasFlag(faultState))
 }
 
+func TestAPPENDWrongType(t *testing.T) {
+	prog := makeProgram(APPEND)
+	vm := load(prog)
+	vm.estack.PushVal([]byte{})
+	vm.estack.PushVal(1)
+	vm.Run()
+	assert.Equal(t, true, vm.state.HasFlag(faultState))
+}
+
 func TestSIGNNoArgument(t *testing.T) {
 	prog := makeProgram(SIGN)
 	vm := load(prog)