R183(5) refers to automatic extension to someone who's applied for a Visitor Record. It does not cover a Spousal Sponsorship/First-Time OWP applicant. While it's not clearly defined by Canadian law (at least as far as I've been able to discover), a SS/First-Time OWP applicant's visitor/temporary resident status is only defined by whatever visitor visa you get when crossing into Canada. As a US citizen I get 6 months. My first-time OWP application provides me no additional status whatsoever.The link above states "If they have done so, their period of authorized stay as a temporary resident is extended by law until a decision is made [R183(5)]." The link therein is to the law (in French for some reason, but it's numbered, so you can find.
What did the superintendent say when they intervened? If you didn't hear, it's possible they were simply not embarrassing the other officer. Frankly the simple answer is quite possibly that the other officer did not know; note also the language of the document linked - it's now called 'maintained status'.
That said, the details of the rest of that policy are rather complex so I'm not comfortable saying exactly whether it applies in a specific case. (I'm just not an expert)
That link and the relevant sections of the law should be what you'd need.
My US residence is in a very unique spot in relation to Canada, and crossing the border multiple times a day year-round (pandemic notwithstanding) is the norm there. And while technically I'm only allowed 6 months per year in Canada, all of the long-time CBSA officers recognize that this is impossible for residents of this unique US location, and they use their discretion to ignore the 'law' while we residents cross the border almost daily. The Superintendent who intervened is well known to me, and has waved me through this crossing hundreds of times over the last few years. The CBSA agent who was getting technical on me was unknown to me. Pretty sure the Superintendent reminded the agent he had broad discretionary power, and that letting me cross despite technically overstaying my stay was within his purview. After their sidebar chat he gave me a stern warning and suggested I apply for a Visitor Record to extend my status.
Interestingly, when I try to apply for that extension, it requires me to log into my gckey account and takes me to a questionnaire. When I answer all the questions it indicates I should apply for Spousal Sponsorship instead of a Visitor Record and dead-ends me et a link to begin the PR application process. The only way I can apply for a Visitor Record is to lie on the questionnaire and indicate that I intend t stay only temporarily.
I appreciate the discourse on this subject.