completeRollback method for destination MigrateDestinationFile()?

I try debug my migration script and this seems completeRollback() method is never called in my migrate code.

I'm working on migration files, where i read data from MongoDB source and for better migration performance i write new key drupalMigrationDestinationID to mongo document in complete() method. In rollback i want remove this key but this seems my completeRollback() method is never called.

For migration articles (to nodes) work this method perfectly, but there is problem with files.

(I use drupalMigrationDestinationID key as flag about already migrated documents, performRewind() method return only documents without this flag, then getNextRow() method don't need read every migrated row again after migration continue.)