On backup, a link like http://MYSERVER.fr/moodle/mod/resource/view.php?id=831 in the description field
of a database activity is changed to $@RESOURCEVIEWBYID*831@$ in the backup file.

On restore, this is then supposed to be changed back, but using the new id.

This was not being done for a database activity either by backup/restore nor by using the new importation option.

This relates to http://tracker.moodle.org/browse/MDL-9432 where that bug was also reported for quizzes.