I think it could be one of two things, either early prototypes that Nike are just trying to get rid of, but I can't imagine that being the case from the official store and them not being labelled as such.
The other thing it could be is a 'code-7' shirt, these are usually shirts that contain small differences from the final product and are almost the same except for a few finer details like maybe a different collar.
Check out this code7 Inter shirt and compare it to the real thing so get what I am on about
www.subsidesports.com/uk/03-04-inter-milan-home-shirt-code-7.html