top stair tread issues

[aardvark102431]

Hi folks,
I seem to be consistently having this problem with my stairs in various projects. It's probably a small fix but I just can't seem to figure it out. It appears as thought the overhang of the very top tread (hence the finish floor that the stair is going up to) will not match the material I have chosen for either the stair tread or finish flooring. I usually end up with a white "strip" as you can see in the photo. Any ideas on how to fix?
Thanks,
Greg