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All this just shows what I've been saying many times (and what dpenabill is saying above): IRCC employees are humans who read your forms. There is no point in freaking out over every single word.

Of course you should still try your best, but what I mean is that there is no need to worry about every tiny detail after you sent the application.
I agree
 
Correct dates:
Sep 2013 to Oct 2017 - address 1

Oct 2012 to Aug 2013 - address 2

What I put in the application:
Sep 2013 to Oct 2017 - address 1

Oct 2012 to Aug 2012 - address 2

Clearly, 2nd entry will cause a gap and date range is incorrect and not plausible. Not sure if they overlooked this.
Don't worry, it might not be a problem at all.
 
Just got the below repose from cic for my webform request to correct the dates:

Good day,



Thank you for contacting Immigration, Refugees and Citizenship Canada (IRCC).



We verified the information you provided and have forwarded it to the responsible office.



They will contact you if further information is required or if a decision is made on your application
.

I hope everything goes well.
 
Thank you razerblade. I've submitted Webform with the correct information. I hope they take this into consideration.
You got the correct mess without any issue.plz let me know .I also have error I got aor 2 days ago now I found there is error in passport detail due to typing it is showing country of issuing as Indonesia instead of india. Rest every detail are correct .what to do plz share your exp about webform and how they reply