When editing an object, going to the features tab, and selecting a physics preset (Stone, Wood, Etc.) it changes it accordingly. When you open different objects that have linked parts, it shows the last preset you selected in the grayed-out field. When you edit linked, select the first link, it will then show you the true existing preset selected for that object. Whatever you selected in a previous edit always shows for all linked objects until you change it.
If you build, for example, a cube, but delete that cube before you close the build menu, that preset field will be blank for all linked objects until you edit any object and change it. When you edit linked and go to the first link, it now sets whatever was in that preset field to that instead of the blank.
Relogging does not reset this behavior. It appears to save that information in the system because I have logged into the SL Viewer and the Firestorm viewer and determined that state persists. I have attached screenshots from both viewers showing the same thing.
This is real problem for landscapers because when I am changing those physics settings for many different linked objects, for each linked object I have to edit linked, go to the first link to see if I have already changed it or not. It should show the first link's existing setting, not the last one used to change something else.