The officials have several discussions with experts when drafting a bill. It's somewhat like what happens with amendments proposed during committee proceedings. Bills are drafted by experts from the House of Commons Procedural Services. Committee members thus receive a text drafted by a legislative expert from the House of Commons, and this helps them promote their ideas.
Something quite similar takes place in the department. Its jurilinguistics service is responsible for conducting an important phase of a bill's revision, and this topic is discussed at length. Considerable effort is made to ensure that the two texts say exactly the same thing in both official languages.
Errors occur from time to time. To correct them…
I'll say this in English because I don't know the name of the statute in French. It's the statute amendment act, which allows for some of these corrections to be made. From time to time, there's been an error in the specific meaning.