Another air travel entry shows incorrect entry time adding a day.
Reminder: date of entry into Canada is NOT the date a person physically arrives but is the date the traveler actually clears border control. A traveler has not actually "entered" Canada until PoE officials actually grant permission to enter Canada.
Discrepancies related to this generally involve arrivals just before midnight when the traveler does not get through the PoE examination until after midnight. (More common error made is in regard to exits, where some rely on a passport stamp showing date of arrival in another country; this is often off by a day for red-eye flights and can be two days off from the actual date of exit for trans-Pacific travel.)
The best the applicant can do is make sure to COMPLETELY and as ACCURATELY as possible report ALL dates of exit and dates of entry, and as @Mexontario suggests, wait to apply with a good margin over the minimum required physical presence.
To the extent an applicant is not certain his or her own records are complete and accurate, the prospective applicant can check and compare information from a variety of sources. But of course the one and only FOR SURE source is the applicant himself or herself. He or she is the only one who was FOR SURE there each and every time.
Of course if the prospective applicant did not keep a COMPLETE and ACCURATE record of every entry and exit, that means the one best source of this information is not an entirely reliable source. How big a mistake this can be varies widely. For many if not most, it is fairly easy to use other sources to help reconstruct and verify travel history, to at least get it close enough that in conjunction with having a decent margin over the minimum, IRCC is not likely to have concerns.
The key is to report dates as COMPLETELY and ACCURATELY as the applicant can. The less certain the applicant is, the longer the applicant should wait to apply in order to have a bigger, more comfortable margin over the minimum.
