Mostly: As long as you send off documents responsive to the request, per the instructions, within a couple weeks or so, there should NOT be any problem due to how long it has taken you to send in the response.
(Whether there is a risk some other issue might arise and cause problems is a separate matter; but a short delay in submitting the requested documents should NOT, not in itself, cause any problems or significant delay.)
As I will explain below, it will help advance our understanding,
@Real55, if you could specify or describe more about what documents in particular were requested. Among those of key interest, relative to the nature of the request you received, is whether the request asked for documents like Exit/Entry Records from other countries or documents to prove where you were living (rental or ownership documents), or documents such as history of health care usage, or documents to prove your employment in Canada.
Further Observations:
On one hand you provide more detail than many others have about the actual request, and related communications with IRCC, and this helps. But whether your PR card application will face delays or how the situation might otherwise affect you, that depends on many other factors specific to your situation. (By the way, while it is not a good idea to share too many personal details in a venue like this, the more detail there is with a query, the easier it is for forum participants to identify the relevant issues and provide helpful information; so longer queries are often better, definitely better than a too short query which fails to disclose key elements, and importantly they help advance our understanding of the process generally.)
Assuming the delay in sending off your submission of requested documents is NOT lengthy, and what you submit satisfies the request, this should NOT delay the process by much. But of course it is important for you to
FOLLOW the INSTRUCTIONS and submit the documents requested as soon as you practically can. The longer it takes you, the longer it will take IRCC. That much is hardwired into such a request.
Thus, there is already some delay. At the least there is the amount of time you are taking to submit the requested documents. There is quite likely also some queue involving some waiting for action to be taken on your file AFTER IRCC receives the response.
As for missing the deadline, or getting an extension, not all deadlines are created equal. It can be dangerous to miss some deadlines, while other deadlines are inherently soft or at least not a strict deadline. Most procedures involving requests for additional submissions allow for a significant buffer beyond the deadline and typically no IRCC personnel will take action on the file until some time after that buffer has passed, and sometimes this is actually a formal part of the process where there is a BF date assigned, pursuant to which the BF (Bring Forward) date is typically well past the deadline.
REMINDER RE ROUTINE PRC PROCESS:
The routine PRC application is largely done virtually all-at-once. Technically it is a multi-step process, but in practical terms the routine PRC application is opened, reviewed on-its-face in conjunction with IRCC information at-hand (largely GCMS including FOSS, perhaps also including access to CBSA Travel History), a positive decision is made, a new PRC issued, and mailed. Done. This involves some distinct administrative steps, but again in practical terms the main wait time for routine PRC applications is the queue waiting for a processing agent at PRCC-Sydney to actually open the application. Then there is just the amount of administrative time it takes for PRCC-Sydney (or such) to actually physically create the new PRC and put it into the mail (noting that, according to last disclosed IRCC information,
TEN percent of these are randomly selected and sent to a local office to be delivered in-person rather than mailed directly).
What you describe (albeit also subject to the particular requests) appears to indicate your PRC application is still largely in this track, an almost-routine track, EXCEPT for the request, suggesting that so long as you TIMELY submit documents responsive to and otherwise satisfying the request, the PRCC-Sydney will proceed to approve the application, issue a new PRC, and probably mail it. NO particularly lengthy delay. NO special or secondary review. (Of course, a processing agent assessing the information and submitted documents may still perceive a reason for ADDITIONAL REVIEW, which would constitute further review and some further delays.)
Which brings me back to my continuing effort to clarify differences in the type of review involved in PRC applications.
ADDITIONAL REVIEW: BEYOND DISTINGUISHING SR AND PR RO REVIEW
In this regard, some of the detail in your query,
@Real55, is particularly helpful.
There are actually MULTIPLE types of review which can be part of the PRC process. This particular topic is intended to be about
Secondary Review. For nearly FOUR years now, however, queries and observations in this topic have been in reference to multiple types of review, often without clarification about which type of review, and all the while plagued by an overall confusion having to do with failing to distinguish two types of review:
-- the PR receives a notice of "Secondary Review" BUT NO request for additional information or documentation, versus
-- the PR receives a request for additional information or documentation relating to residency or presence or travel history
Detail in your query really helps clarify that some of the queries and observations here may NOT be about either type of additional review, but are simply about a PRCC-Sydney request for documents, for verification purposes. And, indeed, this could explain the difference between those instances in which the PRC is issued, mailed, and received within a month or so versus those which take significantly longer. (It appears to me that this sort of request may be one of the possibilities
@sunnybh was referencing, rather than a referral for SR or other Additional Review.)
In this regard, as I mention above, it will help advance our understanding, Real55, if you could specify or describe more about what documents were requested in particular. Again, among those of key interest, relative to the nature of the request you received, is whether the request asked for documents like Exit/Entry Records from other countries or documents to prove where you were living (rental or ownership documents), documents such as history of health care usage, or documents to prove your employment in Canada. It would also help if you could clarify whether the communication from IRCC specifically mentioned a "referral" for "review" and if so, quote the precise terms.
The latter request is also extended to all other forum participants who have received communication from IRCC regarding a PRC application which has been referred for any kind of additional review. Please clarify what the precise language is in the communication, such as whether it literally states the application has been "referred," and what it has been referred to or for. For example, does the communication specifically state "Secondary Review?" It is obvious that the discussions here reference procedures in addition to the two groups or types for which I have tried to emphasize the differences. So it will help advance our collective understanding considerably if the precise terms are shared, so that the various anecdotal reports can be put into perspective, illuminating more clearly how the system works.