Questions about living or working abroad while an application for citizenship is pending tend to be tricky.
As some have noted, being abroad AFTER applying has no direct bearing on an applicant's qualifications for citizenship UNLESS the applicant is abroad so long there is an issue about compliance with the PR Residency Obligation.
There are, however, some serious risks and pitfalls, with logistical factors looming large, and whenever it is apparent an applicant has returned to Canada from abroad to attend a test and interview, there is a risk this might trigger a processing agent or Citizenship Officer to at least question the veracity of declared days present in Canada.
Beyond what should be the obvious logistical risks like not getting notices in time (which, nonetheless, many seem to underestimate and then run into problems when they miss deadlines to submit documents or fail to show for a scheduled event), how much risk there is NOW, for current applicants, is very difficult to discern. This is one of those situations in which anecdotal reports only reveal what is POSSIBLE, and not necessarily what is likely, definitely not what the rule or policy is, and especially NOT for-sure how it will go for someone else.
In particular, while anecdotal reports from SOME who successfully navigated the process and became citizens, even though they were living or working abroad after applying, suggest this is NOT as big a problem as it tended to be in the past, it would be prudent to approach this cautiously and, in particular, BEWARE these reports are way, way short of any guarantee how it will go for someone else.
Some History:
Historically the risk of triggering RQ, the formal procedure CIC followed when a reason-to-question-residency (or presence) was identified, was indeed a big risk. The Liberal government implemented screening criteria as far back as 2005 pursuant to which indications the applicant had recently returned to Canada in time to attend the test/interview event were specifically deemed a reason-to-question-residency. A decade later, in 2015, the Harper Conservative government went a step further and adopted an intent-to-CONTINUE-residing-in-Canada requirement which, while widely misconstrued as affecting new citizens (it did NOT), essentially gave CIC (before the transition to IRCC) overt grounds to deny an application if the applicant was living abroad after applying (it is impossible to CONTINUE residing in Canada if someone is not currently residing in Canada, and of course one cannot intend to do that which it is NOT possible to do; thus, merely living abroad while the application was pending would give CIC enough grounds to deny the application). This provision was short-lived and was among the first things the Liberal government repealed.
But it warrants noting that the impetus to repeal the intent requirement was far more about its bad optics than its substance. As I noted, living abroad while the application was in process had long, long been a factor tending to trigger concerns, questions, even overt skepticism, causing non-routine processing, much longer timelines, and potentially leading to a Citizenship Judge hearing in which it would be up to the CJ to decide, in essence, whether to believe the applicant's account or not. This was during BOTH Liberal and Conservative governments.
Now it is entirely feasible that the current Liberal government's approach incorporates a policy in which living or working abroad, after applying, is NOT considered at all, is essentially ignored. I doubt this. But I do not know.
Other changes in the law, over the years, have diminished the significance of living or working abroad after applying; the big one is that there is NO RESIDENCY requirement, now, as such, but rather a strict physical presence requirement. Residency abroad after applying, for example, has less relevance to where one was physically present before and up to applying. Whereas, under the old law, indications of residency abroad inherently raised questions about when, in particular, did the applicant cease to maintain residency in Canada (technically, when residency was the requirement, CIC and a CJ could deny credit for time present in Canada if the applicant was not, at that time, also an in-fact resident; in particular, presence in Canada before establishing actual, in-fact residence in Canada did NOT count; and while there were not many cases, there were some in which presence in Canada after it appeared the applicant established residence in another country was NOT counted, such as where the individual obtained a U.S. Green Card).
BUT of course, if and when an applicant arrives at the test/interview and it is apparent the applicant is now living abroad, at least some processing agents or Citizenship Officers are bound to have questions about when, when-in-fact, did this individual move out of Canada, and thus, wonder to what extent the applicant's declarations about presence in Canada (during the "eligibility period") can be trusted. This risk is mostly about being subject to non-routine processing, leading to a much longer timeline, potentially including the dreaded full-blown RQ (CIT 0171), which is profoundly intrusive into one's privacy and profoundly inconvenient as well.
Which leads to another historical risk, which may or may not be a continuing risk: the process taking so long that the applicant fails to stay in compliance with the PR Residency Obligation and thus becomes ineligible for citizenship before getting an opportunity to take the oath. Since processing timelines are generally a lot faster these days than they were during the Harper years, for example, this appears to be a lesser risk these days. Unlike back then, when especially RQ'd applicants might anticipate their applications taking THREE PLUS years (thus long enough for them to no longer be in compliance with the PR RO if they were living abroad in the meantime), these days there appears to be little risk the timeline will approach let alone exceed three years. The caveat is that we are not seeing what the timeline for non-routinely processed applications really is these days. Thus, those applying now for citizenship and moving abroad should be aware of the possibility they will encounter non-routine processing AND if so, AND if the non-routine timeline approaches three years, the applicant will need to adapt and be sure to return to Canada enough of the time to avoid any issue with PR RO compliance.
Particular factual matters, like reporting place of residence:
The reported address history and work history, in the application, are historical, PAST tense up to the date of the application. So there is no need for an applicant to notify IRCC, for example, that the applicant has changed employers or the location where the applicant works.
But the application does call for the applicant to declare his or her place of residence. And of course this can change. And this is a material fact. And the applicant's signature verifies the applicant will timely notify IRCC of any changes in the information provided.
So applicants are required to notify IRCC if and when they change where they actually live, where they in fact reside.
Many do not. Many use a family member's address. Or a close friend's address. Obviously, to some extent this is misrepresentation (declaring a place as where one lives when one does not actually live there). How seriously or strictly does IRCC approach this particular issue? It is well apparent many have NOT run into problems with this. It is also apparent, however, this could cause problems if a processing agent or Citizenship Officer focuses on it.
So this too is about RISKS. Not rules. No definitive way-it-works. Rather, it is about if and when, or why, some are OK, and some run into problems.
My sense is that the best approach is to be forthright and truthful, to play no games. But, my impression is that among those who have moved abroad while the application is pending, many apprehend notifying IRCC they have changed their residential address will trigger problems, at the least some questions and delay, and thus they continue to let their application record show a Canadian address (family, friend, or consultant). How it will go for them is a GUESS. Whether questions about current employment or current address come up in the interview, and what impact this has when it does, probably varies from one applicant to another, from one local office to another. To some extent this is one of the logistical hurdles the applicant faces when he or she moves abroad while the application is pending.
OVERALL: I have taken the long way round to highlighting the fact that even though being abroad after applying has no DIRECT effect on qualifying for citizenship (again, unless a PR RO compliance issue develops), there are RISKS and PITFALLS lurking for the applicant who is living or working abroad while the application is pending. How it will go for any particular individual is almost impossible to forecast. More than a few are reporting it has gone not just OK but routinely, no problem. That is no guarantee it will be so easy for anyone let alone everyone else.