I respectfully disagree.
You have quoted, accurately, this impeccable source:
https://www.canada.ca/en/immigration-refugees-citizenship/services/application/application-forms-guides/guide-5289-sponsor-your-spouse-common-law-partner-conjugal-partner-dependent-child-complete-guide.html#eligibility
So, as I apprehend the relevant law and policy, a citizen can live outside Canada for the entire duration of the process, if able to show intent to live in Canada "when your sponsored relative becomes a permanent resident." It does not say that leaving for more than a "short vacation" will be fatal to the application. And it better not. Putting such a clog on a citizen's mobility rights would be an affront to common sense, if nothing else.
As for sponsors who are permanent residents, then, in my view, they are not forbidden from taking a lengthy vacation. The prohibition arises for those "living outside Canada". I will venture what follows, in the context of the OP's query.
The OP says the sponsor is "in Canada" and asks if okay to "travel", not move to, relocate to, etc., another country. So, if we assume the OP sponsor is a permanent resident, and not a citizen (we are not advised of this status), then, certainly, what most would consider "travel" should be okay. Next, I'll draw a longer bow and submit that said "travel" should not, of needs, be restricted to what some here have suggested be a "quick vacation" or "no more than a few weeks". Why should that be, so long as one does not fall afoul of the "living outside Canada" injunction?
Canada is notorious for making it difficult for sponsors to bring their spouses to Canada to visit during the inordinately long sponsorship and permanent resident application processing times. CIC is most parsimonious in granting TRVs so that spouses can have time together during the processing period. So, the only way to be together is for the sponsor to leave Canada to be with said spouse. Can CIC be so punitive as to decree that thou shalt not be together for more than a "quick vacation" in that time? I would hope not.
I will accept the notion that optics play a role. If the sponsor submits the application, then quickly departs Canada, leaving little trace of "living in" Canada behind, then the application might be in jeopardy if the sponsor remains abroad for an extended period. For example, the sponsor gives up any home here, gives up any employment here (apart from approved vacation or leave of absence), closes bank accounts, sells car and otherwise abandons most indicia of "living" in Canada, then I can see the application being at risk.
At the end of the day, I can see the matter of who is a "permanent resident living outside Canada" being a fact-driven inquiry, to be decided on a case-by-case basis, and guided by common sense. The OP asked quite a simple question and I think we have added, perhaps, some unnecessary layers of complexity by delving into nice questions involving matters such as permanent resident status v. citizenship status of sponsor. I am guilty of making more of a labour of the inquiry than called for. I had hoped my single-sentence initial reply might serve. It appears, at least to some, to have been too facile. Perhaps my musings set out in this more prolix post will remedy that.
