Asking users to sign in when already logged in

This is a rather confusing user interface element:

• The presence of my name indicates to me that I am logged in
• The presence of the "Sign in" link indicates to me that I am logged out

eBay isn't the only site that does this. I've noticed that Amazon does this too.

It appears that this happens upon my session timing out, however I also notice that my session hasn't completely timed out. For instance, my name and postal code are still remembered as the calculated price including shipping is available when I browse through items. In this half-authenticated state, I can't add items to Watch List, bid, etc.

Is having this half-authenticated state a good idea? Can improvements be made to the greeting/sign in UI as indicated in the attached image?