1) What happened
When using standard MSAA in the Unity quality settings, with forward rendering, I'm getting a 1px white border between my object and its shadow. This is on a Radeon 5850. Changing the shader between diffuse or specular makes no difference, and neither does implementing the specular shader fix which some people have posted on the forums for a similar issue (adding o.Normal = fixed3(0,0,1);).
Using no AA, FXAA etc, are all OK and have no issues.
2) How can we reproduce it using the example you attached
I can't get a sample project to show it as well as my own projet does. On the attached project, the white border is obvious on my machine between the bars on the model and the shadow on the base if angled right, but the shadow on the ground looks OK.
Here is an image showing the issue in my main project: http://i.imgur.com/le7jJ.jpg