`<stacktrace>` fails to load `.pdb` of shared library

I'm going to use std::stacktrace in a .dll whitch is loaded by LoadLibrary.
While I have followed the instruction from a previous issue #2779 and passed /PDBALTPATH:%_PDB% to link.exe for two binaries, the .pdb file fails to load correctly.
The current directory structure is:

C:.
│  test.exe
│  test.pdb
│
└─so
        dll.dll
        dll.pdb

sources of the two binaries is:
dll.cpp

#include "head.h"
#include <stacktrace>
#include <iostream>

DLL_API void ps() {
    std::cout << std::stacktrace::current() << std::endl;
}

test.cpp

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <iostream>
#include "head.h"
int main() {
    auto hModule = LoadLibrary("./so/dll.dll");
    if (!hModule) {
        std::cerr << "Failed to load library" << std::endl;
        return 1;
    }
    auto func = reinterpret_cast<decltype(&ps)>(GetProcAddress(hModule, "ps"));
    if (!func) {
        std::cerr << "Failed to get function" << std::endl;
        return 1;
    }
    func();
    FreeLibrary(hModule);
    return 0;
}

head.h

extern "C" {
#ifdef _EXPORT
#define DLL_API __declspec(dllexport)
#else
#define DLL_API __declspec(dllimport)
#endif

DLL_API void ps();
}

And when I run test.exe, it prints something like:

0> dll!ps+0x4A
1> C:\space\projects\cpp\st\test.cpp(18): test!main+0x7E
2> D:\a\_work\1\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl(288): test!__scrt_common_main_seh+0x10C
3> KERNEL32!BaseThreadInitThunk+0x1D
4> ntdll!RtlUserThreadStart+0x28

, indicating that dll.pdb is not loaded correctly (otherwise it should print the directory of dll.cpp).

Since the document of std::stacktrace is missing, is there any solution?

Start with the provided dll.cpp, test.cpp, and head.h reproduction, including the LoadLibrary call and /PDBALTPATH:%_PDB% linker option. Build and run test.exe with dll.dll and dll.pdb in the shown so directory, then inspect how std::stacktrace resolves the shared-library frame. Done means the frame for dll!ps resolves to the directory and line in dll.cpp.