So when they miss a record thats what initiates more scrutiny and potentially this RQ by IRCC? I read about RQ somewhere in this forum.
Under what conditions they send an RQ is anyone's guess. But based on past posts on this subject, it seems like if the entry was recorded by either the CBSA or the US CBP but the applicant missed it in their citizenship application, that appears to be a trigger.
It seems like RQ requests of all kinds have quieted down a lot likely because CBSA now gathers a lot of entry/exit information they weren't previously capturing. One can also speculate given the travel restrictions during COVID means most people stayed put especially the leisure/other non-essential trips to US probably went to zero during this period.
My guess is their passport request for all pages during the eligibility period serves the same purpose an RQ did before 2020.