This is the Google way of doing things since android 7.1.
Cannot be fixed. You can still open files directly with old versions of applications. For instance
https://f-droid.org/en/packages/com.amaze.filemanager/ will open the file in Moon Reader without making a copy.
The same happens with old versions of CC (up to 5.3, IIRC)
There's a workaround that app devs can implement to fight against it, but is not recommended for Play Store applications, specially looking at the near future with forced scoped storage.