Is the item that is not displaying correctly a mirrored part at all? There are a few bug reports in the knowledge base on this, so it may not of been fixed when SW2012 was out.
I've personally run into this same issue, and while I haven't fully investigated the problem, I may be able to help. As Myles said, your part is likely a mirror, at least that's how this error appeared for me. I think the problem may lie in Step 4 of the Mirror Components tool. In comparing between having the "Custom Properties" box checked vs. unchecked when creating the mirrored part, I found that with the box checked I would be unable to get rid of the "fromparent+" description, but when the box was unchecked, I was able to set the description to my own liking. Using the "Break link to original part" box may also be something to experiment with.