I have found similar behavior for other properties as well. To add to the information, I am populating the property value with a macro using the CustomPropertyManager : Add3 method. I tried using both the ForceRebuild3 and the EditRebuild functions. I tried each in both the standard (rebuild only what's needed) mode and the force rebuild (rebuild all) mode without success. Even the old standard, ctrl-Q does not work.
One thing that WILL work, is to click on the property in the "value" column, and the "evaluated" column will update to match.