Given that piece of information is incorrect, you have to do something about it. They will pull up CBSA records to cross check all your dates as part of routine processing. It's definitely not to the level of misrepresenting criminal records but if it gets in the wrong hands, the office can argue you intentionally misrepresented being in Canada.
1. If you are sure rules prevent you from applying outside Canada, withdraw the application as soon as possible while also mentioning you were unaware of that requirement before and as soon as you are aware, you are applying to withdraw. You previous withdrawals might be looked at during your future applications so you have provide a proper explanation while withdrawing.
2. If you know there is a way around that requirement and you qualify for it, file a correction about that return date and saying you were applying from abroad and qualify for an exemption.
I think 2 is unlikely but I don't know the rules.
If you delay, it may become a problem with future applications especially if it gets in the hands of someone who doesn't look at these mistakes too kindly.