missing output in the eclipse console when debugging

I recently started using Eclipse CDT (version 2019-03) with the Cygwin toolchain and have noticed some bizarre behaviour when using the debugger.

Under the debugger the following program behaves as you would expect

#include <iostream>

int main()
{
    std::cout << "hello world\n" << std::flush;
}

However the following produces no output

#include <iostream>

int main()
{
    std::cout << "* world\n" << std::flush;
}

And for the following the output is world

#include <iostream>

int main()
{
    std::cout << "@ world\n" << std::flush;
}

This behaviour is completely consistent and reproduceable. Does anyone have any explanation or workarounds?