There is no official or authoritative timeline information regarding RQ'd cases in particular.lenium said:
Timeline information provided by CIC as to "non-routine" cases is far too indefinite to be informative. Moreover, there have been so many changes, with more to come, that historical timelines are in general not a reliable indicator of much.
It is easy to guess that RQ cases will not take nearly so long as they have been taking in the past four years, but that is in large part because the processing of residency issue cases was deeply bogged down and timelines for tens of thousands of RQ'd applicants were grossly excessive. There was no direction the timeline could go but get at least a little faster. And the timeline for non-routine cases, including RQ'd applicants, does appear to have improved significantly, if not considerably . . . but again that is not necessarily saying much since it was more like a parking lot than a highway for so long.
Additionally, the timeline will continue to vary considerably relative to the specifics of the individual case.
Thus, overall: No one can credibly predict how long it will take to process your application. How long it has taken other RQ'd applicants is not at all a reliable indicator of how long it will be for more recently RQ'd applicants generally, and again the timeline varies and will continue to vary considerably relative to the specifics of the individual case.
Observations about erroneous stamp date et al:
This can be an easily resolved issue or, as discussed further below, a difficult one, DEPENDING.
If a CBSA passport stamp was erroneous, this should be easily resolved by the CBSA travel history which is very, very unlikely to be erroneous (CBSA travel history may have omissions but the dates reflected for entries into Canada are almost always accurate). That is, CIC should be able to verify the accurate date of entry fairly easily and in short order.
Now that you have been RQ'd, CIC will (if it has not already) access your CBSA travel history (assuming you gave CIC authorization, either in the application or in the RQ form, usually both these days). So, if the only concern is this one discrepancy, that should be resolved.
Of course you have to fully respond to the RQ, since once RQ is given to an applicant all the elements of residency are in issue, and the burden is on you, the applicant, to affirmatively document (prove) you were resident-in-Canada when you declared you were.
But if that single discrepancy is the only cause for concern, is clearly resolved, sending a responsive submission for the RQ, following the instructions of course, should suffice to get your case processed in due course with a favourable outcome.
Caution/Caveat:
The following is in large part based on the assumption that the CBSA stamp in question is an entry stamp, not an exit stamp, since it is rare for PRs leaving Canada to have their passport stamped by CBSA upon exiting.
It is not uncommon for RQ'd applicants to underestimate the issues or concerns in their case.
Which leads to the observation that while a discrepancy in itself tends to raise issues, in terms of physical presence in Canada the discrepancy here adds to your time present, the CBSA stamp indicating entry into Canada 10 days sooner (March 03) than the accurate date (March 13). So it is curious that this discrepancy alone would trigger a full RQ, particularly these days when CIC is using an alternative form to request particular documents rather than issue a full RQ in many instances.
Even if someone at CIC appeared to say just what it is that triggered RQ in your case, that should not be relied upon. CIC is generally discreet, if not outright secretive about its reasons for issuing RQ. Sometimes the reason is indeed overtly obvious, and if this discrepancy was the other way (stamp erroneously reflecting an entry 10 days later than the actual entry), that would be a more obvious cause for issuing RQ.
All I am saying here is that you probably want to review your copy of your application, thoroughly, and the residency calculation you submitted, and consider your history and circumstances specifically looking for issues (most people tend to review their own case looking mostly at what supports it, but if you want to go forward prepared for what may be coming, it is best to approach assessing your case from a perspective as critical, as negative, as you can muster) to be sure things are in order or to identify (as best you can) what other potential concerns may be lurking in your case.
Further note about the stamp and actual dates: If the erroneous stamp is an exit stamp.
As I noted, much of the response above is based on the assumption that the CBSA stamp in question is an ENTRY stamp, NOT an EXIT stamp, since it is rare for PRs leaving Canada to have their passport stamped by CBSA upon exiting.
I recognize that there is some incongruity in making an assumption that the stamp in question is an entry stamp if you applied on March 06, in-between the March 03 and March 13 dates you refer to in your post (which your post seems to suggest), indicating you were in Canada on March 06, which of course is after March 03 and before March 13 . . . suggesting that the error has to do with the date of leaving Canada.
If indeed it was a rare instance in which CBSA stamped your passport on exit, depending on where you traveled to on that occasion, it would be likely there would an entry stamp for the country of destination, so an error in a date of exit stamp should be readily recognized as such (unless one infers you spent ten days in limbo at an airport waiting for a connection, and so your entry stamp is dated March 13 or later even though you exited, according to the stamp, March 03). That is, there should be an entry stamp in another country within a short period of time corresponding to the date of the exit stamp from Canada, and that should corroborate your account or declaration as to the date of exit from Canada.
If, however, this is indeed in issue, a problem, it may be prudent to directly address this particular time span in the response to the RQ, separately with a short, fact-based explanation on a separate page of paper. If CIC believes you left Canada on March 03 and the application was dated March 06, that is not merely a discrepancy in declared dates of travel, not merely a loss of three days of actual physical presence in the residency calculation, but that implies, at the least, a post-date application and that someone did the mailing on your behalf (who should be disclosed as someone assisting in the preparation and submission of the application). Thus, it would be prudent to have included in the response to the RQ, even though the instructions may not have directly requested such documentation, some document to show you engaged in an activity in Canada during that ten day time span, and short of having direct documentation of this (doctor or dentist visit, meeting with a lawyer or accountant, a speeding ticket, almost anything from an objective source), perhaps including a sworn statement from a credible person who could affirm your presence in Canada during that time (letter from a member of clergy or other religious leader, letter from employer you were at work that week, or even a letter from neighbours, friends, or family if you have nothing from a more objective source).
Note: CBSA travel history may or may not, leaning toward probably not, reflect the date of exit. So if indeed this is about an erroneous stamp for a date of exit, it can be a bit more difficult to document the correct date.
