I am NO expert and I do not know the status of any particular applicant. I do not know precisely what any CBSA or other Canadian officials have stated.
In particular, I cannot say whether the CBSA officer stated that "citizenship is granted" or whether @mimika *understood* that based on whatever particular words the CBSA officer said. Even officials can be sloppy in the language they use.
Most likely, almost for sure, as @mimika clarified, the CBSA officer was saying that the decision to grant citizenship has been made. And, as @mimika further clarified, notwithstanding the decision to grant citizenship, the applicant is NOT YET a citizen (meaning citizenship has not yet actually been granted) until the formal grant of citizenship which requires taking the oath of citizenship.
The reason I am addressing this, however, is to further clarify, and do so with some emphasis, that the decision to grant citizenship is provisional, NOT FINAL, and in particular is contingent on the applicant continuing to meet the qualifications for the grant of citizenship right up to taking the oath.
The main conditional factor at stake, at this stage, is continuing to NOT be subject to any prohibitions. For example, an arrest for domestic assault or driving while impaired the day before taking the oath will constitute a prohibition, making one NOT eligible for the grant of citizenship.
Another factor which can preclude being eligible, and thus preclude the applicant from taking the oath, from becoming a citizen, is a breach of the PR Residency Obligation (this has mostly popped up during periods of time when application processing was extremely slow, like during Covid, affecting some applicants who moved outside Canada after applying and were outside Canada long enough to run into RO compliance issues).
There are many reasons why a scheduled oath might be cancelled, ranging from reasons affecting whole groups of applicants (technically "candidates" once they have been scheduled to take the oath), to reasons for cancelling the scheduled oath particular to the individual candidate. Thus, they can range from situations in which a Citizenship Judge is unexpectedly unavailable (personal illness, family emergency, all sorts of possible reasons), to something popping up in the candidate's GCMS records when the final GCMS background check is done, with a wide, wide range of possibilities in-between. And IRCC seems prone to administrative stumbling, sometimes scheduling too many at a time for example.
Among some of the more common individual factors appears to be IRCC learning the candidate is outside Canada, but again there are many other possible explanations for why a scheduled oath is cancelled (most but not all meaning it is postponed, to be rescheduled).
