Date modified of my fopx 10.4.8 on Catalina 10.15.3 are not correct. When looking at the package contents of libraries with the same date modified in finder I find differences in e.g. the date of current version.plist. How is that possible? Is there a workaround to reflect changes in the library correctly in the date modified in finder?
The CurrentVersion.plist shows the properties of the current FCP X version your Library is related to (plist stands for Property list). This has nothing to do with the actual work you do inside a Library, it just tells the database what version of FCP X was used when you last worked on your Library.
So it's quite logical that this file does not get modified every time you work on the Library. Let me give you an example.
I have a Library that was created in May 2019 with FCP X 10.4.6. I have just opened and closed that old Library but did not update it to 10.4.8. The Library shows it has been modified today at 15:53. But the CurrentVersion.plist still shows May 25th 2019 as the modification day, which is correct because the CurrentVersion.plist has not been modified. You also will notice that the plist shows 10.4.6 as the current version for FCP X for that Library:
Then I have opened the Library again and I have updated it to 10.4.8. As you see, both the Library and the CurrentVersion.plist have now been modified to the same date and time, and the plist now shows 10.4.8 as the current FCP X version for that Library: