Originally in 2.2 we expected record from files table, it usually comes through $fs->get_file_instance(), the problem is that the new code expects extra joined columns from other tables.

1/ developers must be told how to add the extra columns
2/ when the extra columns are missing we need to fetch them from DB

I believe this is a critical issue that should be addressed before beta, please note I already complained about this before it was integrated.

For example is_external_file() returns bogus information when incomplete $stored_file used in constructor...