Incorrect intelliSense errors depending on include order

Bug type: Language Service

Describe the bug

• OS and Version: Windows 10 21H2
• VS Code Version: 1.68.1
• C/C++ Extension Version: 1.10.7
• A clear and concise description of what the bug is, including information about the workspace (i.e. is the workspace a single project or multiple projects, size of the project, etc).

I've got the following two files, using IAR Systems standard library headers:

// main.cpp
#include <stdint.h>
#include <wchar.h>
#include <memory>

#include "header.hpp"
int main() {
  auto b = ns::B(1);
}

// header.hpp
#pragma once

namespace ns {
  class B {
    public:
      explicit B(const int& a) {}
  };
}

In main.cpp, intelliSense incorrectly complains that the namespace ns does not exist:

If I open header.hpp, where ns is defined, and go back to main.cpp, the error disappears for a while. If I browse some other files for a while, the error reappears.

Interestingly, the problem only occurs when <memory> is included last of the standard library headers. Removing any of the includes or including <memory> earlier gets rid of the intelliSense error. main.cpp compiles correctly in all cases.

Steps to reproduce
Here is an example that reproduces the problem:
cpptools_errors_from_include_order_example.zip
It includes all the necessary files, including the c_cpp_properties.json and all required IAR standard library headers.

Simply open main.cpp and observe the intelliSense error.

Additional context
This may be related to https://github.com/microsoft/vscode-cpptools/issues/9170. The symptoms are similar, but the workaround of disabling the cache size limit did not work for me.

Öffne die bereitgestellte cpptools_errors_from_include_order_example.zip und untersuche main.cpp, header.hpp, c_cpp_properties.json und die IAR-Header; beginne damit, den falschen ns-Fehler zu reproduzieren, wobei zuletzt eingebunden wird. Als abgeschlossen gilt, dass IntelliSense für das bereitgestellte Beispiel nicht mehr meldet, dass ns nicht existiert, während das Projekt weiterhin korrekt kompiliert wird.