boost::filesystem on WSL - Function not implemented error

This follows code snippet is behaving quite weird on two platforms WSL and Ubuntu

#include <iostream>
#include <boost/filesystem.hpp>

int main(int argc, char **argv)
{
    try
    {
        auto cp = boost::filesystem::current_path();
        if (boost::filesystem::is_directory(cp))
        {
            std::cout << cp << " is a directory \n";
        }
    }
    catch (std::exception &e)
    {
        std::cerr << " Problem ? :: " << e.what();
    }
    return 0;
}

On WSL the output is

Problem ? :: boost::filesystem::status: Function not implemented: "/home/kk"%  

while on a Ubuntu VM

"/home/kk" is a directory

Question, is this a bug with boost on WSL or its just the platform thing.