I have come across at least 3 cases in the forum (recently) where DM did not result in straight going to Oath. In one case they were asked to submit additional documents and in other cases it even went back to in-progress... Sorry, I am not able locate those posts now... but I remember reading it... One such a case just happened today morning:
https://www.canadavisa.com/canada-immigration-discussion-board/threads/citizenship-ceremony-not-started-status-since-last-3-months.751242/post-10322526
Wondering whether IRCC is trying to move cases (prematurely) to DM just to meet the numbers. And no one tracks what happens after that? Maybe that explains why people are waiting (more than) 6 months for the Oath? I know, number of people became citizens also being tracked.. Maybe its just a genuine mistake and I am being overly cynical here... But it might be a nightmare for the people when they are told DM is not really a DM.
DM . . . Decision Made . . . happens when a Citizenship Officer approves the grant of citizenship. There are, nonetheless, additional checks attendant scheduling and administering the oath. If at any time after DM, right up to the administration of the oath itself, a question, concern, or issue arises, that will of course mean additional processing and may involve setting the DM aside pending further processing to resolve whatever question, concern, or issue that has come up.
Remember that the applicant must continue to meet all the requirements right up to the administration of the oath. While there are many requirements that once met are not subject to change, matters like prohibitions and validity of PR status remain open questions right up to the moment the oath is taken (for example, a domestic violence arrest the night before the oath is scheduled will prohibit the grant of citizenship).
Moreover, even as to requirements like the physical presence requirement, which once met is not subject to change, likewise anytime up to the actual administration of the oath, IRCC can revisit whether the applicant meets the requirement if it encounters information or reason to question it.
Post-DM-Checks Generally:
For example: As I have often mentioned, last internal information I have seen indicates that IRCC still requires a GCMS check/clearance attendant every action taken on the application, which would include scheduling the oath. If that check triggers a question, concern, or issue, obviously that can result in the DM being more or less set aside pending further processing to resolve whatever question, concern, or issue there is. Remember, for example, the GCMS check includes a name-record check of criminal record databases (which at least covers RCMP and U.S. NCIC/FBI name records), so any hit there will need to be further addressed to verify the "
candidate" (applicant approved for grant of citizenship) has no prohibitions. The GCMS check also screens immigration related history generally, and thus any CBSA flags arising from a Port-of-Entry examination could trigger a question, concern, or issue.
It is less clear, but it also appears that the applicant's Security clearance might expire, or otherwise need to be updated, after a DM but before the oath is scheduled.
EVEN AFTER the Oath is scheduled, some applicants/candidates have had the oath canceled, and one or more of their qualifications revisited. In particular, there is actually a good deal of history, both in anecdotal forum reporting, and in some of the published court decisions, where someone scheduled for the oath does not get to take it (been a long while, but even at my oath ceremony, one of us scheduled that day did not get to take the oath). The usual, typical culprit (so to say) is a question about prohibitions, but there have been quite a few applicants who were abroad and, for this or that reason, CBSA flagged them when they returned to Canada in time to attend an oath ceremony, and instead of taking the oath as scheduled, they were advised their case was subject to further inquiry.
