It appears there are many who rushed applying and are now in a wait and see how it goes mode.
Hopefully some AOR reports will help to put some of the ambiguities and gaffes into perspective, but those are not likely to happen for a few more weeks, and there are so many variables at best they will only offer some idea about things can go, not much about how things are likely to go let alone how they will for sure go.
For those still in the process of preparing their applications: slow down, relax, read the instructions again, and then again, do rough drafts and scrawl "ROUGH DRAFT" across them (so a rough draft does not accidentally get put in the envelope), set the drafts aside for at least a day. Even better to do a completely separate rough draft and compare the rough drafts. A little concentration and patience at this stage can save a lot of anxiety and consternation down the road, and get you to the oath sooner.
Assessing particular omissions in the abstract is near impossible, since so much depends on the context, including particulars (date, duration, relationship to other information, among many more variables). Even an expert (which I am NOT) cannot reliably assess something like this without a lot, lot more information, and even then that would at best offer a range of risks and possibilities. And on top of that, how a particular total-stranger-bureaucrat will perceive it, one can guess but little more.
My comments above about incompleteness are not about how complete the applicant's information is, but about filling the form out completely and attaching all necessary documents. The completeness check only looks for things like the failure to check off or respond to this or that item, or for gaps in work or address history.
Substantive omissions, like failing to disclose work history (especially abroad) or school history (especially abroad) during the eligibility period, are not the subject of a completeness check. The substance of reported history is examined and assessed in the general assessment phase.
Similarly information about having status in other countries.
For these things, when (the date) matters. A student visa prior to the eligibility period should not be a big deal. A student visa during the eligibility period but during a time period the applicant accurately discloses presence and absence from Canada should not be too serious an omission, unless there is something indicating the applicant was abroad in school at a time the applicant was in Canada. These are just isolated examples of other circumstances which can factor into how someone at IRCC is likely to perceive the omission, if and when they discover it of course. (Probably best to bring it up during the interview if IRCC has not already discovered and asked about it, correct the information, and explain the mistake.)
And as noted before, things are relative. Failing to disclose permanent resident status in another country is far more likely to cause concerns than failing to disclose a temporary resident status, since a person with permanent resident status in a country is, of course, more likely to spend time in that country, have ties in that country, compelling IRCC to scrutinize the applicant's history more closely . . . and of course, forgetting to disclose an old student visa does not hint so much that it was deliberate whereas failing to disclose PR status elsewhere is something few would forget about, suggesting its omission is more likely deliberate.
Overall: the omission of this probably is a minor issue. What probably matters more is whether or not, in the scheme of the whole application, it appears to be an innocent oversight or not. How a mistake or omission affects IRCC's perception of the applicant's credibility is huge but very difficult to predict . . . except, of course, big omissions of important details, those are bound to make a very negative impression and seriously compromise the applicant's credibility in the eyes of a total-stranger-bureaucrat at IRCC.
