Funnily it seems to be the reverse of #1520. Here is a snippet:

As you can see, vscode seems to correctly find the location of the stdlib headers, but cannot find the custom headers (they are made available through target_include_directories("mylib" PUBLIC "includes")).

I checked the content of the compile_commands.json file, and if I cd into the directory field from a terminal before running the associated command, everything works out-of-the-box.

Do you have any idea of what could cause this, or any tips that would help give you more useful data?