I need to link some of my custom properties to cut-list properties. For parts created by SW2018 it works fine, I just use "SW-Bounding Box Length@@@CutList@@Configuration Name@Filename.SLDPRT" variable and see actual value in "Calculated" column

But I have many parts created by earlier versions of SolidWorks. I identify these parts by the absence "Link" column in the custom property list. Unfortunately this method does not work for these files.

Ok, let's try add property to cut-list and reference to it from custom property

Wow! It works

But only until I press Ok and close this window. During save my custom properties SolidWorks adds extra "Configuration Name" to property value and it becomes malformed

Is this a bug in SW? I'm using SolidWorks 2018 SP2. May be there is some other workaround?