I have one more observation.
Some super-fast candidates (Sep, Nov 2019 applicants etc) went thru the processes quite smoothly and seem to have already gotten decision made or granted status in the ("whatever") system, and were about to receive some update or notice of DM and/or oath; but suddenly the operations halted due to covid. That's why those super-fast clients, highlighted as bright-green by the system, are now being prioritized than others; although other ceremony-ready clients who'd submitted their applications prior to them and even have 'decision made/granted' status or previous oaths cancelled; however, when it comes to inviting for a virtual citizenship ceremony;
the difference or degree of priority lies in the fact that whoever firstly managed to pass through the system as ALL CLEAR, neat and clean in one-go and got his or her granted status in the ("whatever") system.
In addition, those hundreds and thousands of candidates who finally got 'decision made / granted' status or were about to receive or already had received official notices to take Oath of Citizenship at in-person ceremonies in mid or late March, their citizenship certificates were already printed, dated and ready to be served at a ceremony. Unfortunately COVID-19 came in, and everything got cancelled until further notice. So those unused citizenship certificates, already printed and dated (now backdated) automatically became invalid and would have to be "destroyed / shredded immediately" and new citizenship certificates would need to be issued as per the new customized schedules (varies from client to client) having a specific date on it i.e., citizen with effect from xxxx/xx/xx.
**More relevant info:
https://www.canada.ca/en/immigration-refugees-citizenship/corporate/publications-manuals/operational-bulletins-manuals/canadian-citizenship/ceremony/oath.html