There is an issue with “Preferred values” in components part of library files.
When copies of such a library are created, the components preferred values keep pointing to the source library file.
For example, say we have a “Source Library” with an “Icon” component in it. We set the component with preferred values for icons in that same library.
If we create a duplicate of that source library, rename it to say “Instance Library” - then the preferred values in the “Icon” component from that instance library will still point to the “Source Library”.
There is no indication that the paths to the preferred values are absolute and this might cause a lot of confusion.
Here for examples is the " Preferred values" documentation
I would say the paths to the “Preferred values” should be relative, when set to local components.