The Leader of the Opposition is a public office holder. Therefore, if someone communicates with the office of the Leader of the Opposition, they have to register. Everyone needs to register their intention to lobby the House of Commons, the Senate or certain departments.
What's missing, then, is the communication report. If they have a pre-arranged meeting with someone from that office, they are not required to report it. They are required to register, but not required to report on a monthly basis.