Why composer "psr-4" loading not woking in outer folder

I have this in composer:

"MyCompany\\": ["app/MyCompany/", "app/LaravelPackage/src/MyCompany/"]

and everything works fine. This also works fine:

"MyCompany\\": ["app/MyCompany/", "app/Console/../LaravelPackage/src/MyCompany/"]

Even with non existing folder and path back, works:

THIS IS PROBABY BUG. TRY IF YOU DON'T BELIEVE.

"MyCompany\\": ["app/MyCompany/", "app/Console-babababa/../LaravelPackage/src/MyCompany/"]

But if I move package out of root folder where I run composer install it not works:

"MyCompany\\": ["app/MyCompany/", "../app/LaravelPackage/src/MyCompany/"]

This should work or ?

via Chebli Mohamed