Hi, I lived with my roommate who became my wife for a few years before we applied for spousal sponsorship. She became pr while we were living together as roommate.
Cic asked for a relationship timeline letter, after we replied they approved her as sponsor and gave me aip.
We had proper documentation to prove we were just roommates before ( single on taxes, when we started sharing bills etc...)
All this just to say that like
@Rob_TO said it, they only use the information you provided to them.
You should concentrate on explaining why you did submit a paper with the wrong date and hope they understand.