New
#11
Yeah it's set to stereo.
I don't have any speakers to test at the moment, but I've tried multiple sets of headphones and they all have the same problem.
I'm not sure how to set Left/Right to center, but I've run the test shown in your image and got the bleed over. I've also run the test in Speaker Properties>Advanced tab, Realtek Speaker Configuration, and my own tests in various audio editors all with the same results.