Missing Component Descriptions

I'm using the Custom Property as Component Description option, which I found out about from this post https://forum.solidworks.com/message/16390. I tried it exactly like this https://forum.solidworks.com/message/23164 at first, but it wouldn't work. Our PDMLink populates various fields, one of which is some PTC_WM_NAME that actually identifies the part in a useful way. I'd really like to show those in the feature tree.

So I was very happy to have found a way to do that, until I discovered that Solidworks won't display PTC_WM_NAME for all my parts... just a select few, chosen as far as I can tell at random. The rest it has labeled with a very uninformative "-". None of the parts have any configurations or anything, and every single option under "Tree Display" is checked. This is SW 2010.

Here are some annotated screenshots, the first two of my assembly and the third of one of the Parts Who Shall Not Be Described.

Does anyone have any insight on which of us has gone crazy, SW or me?

SolidworksParts And Features