Hi Samin,
We have had the same experience..... my sibling who is a Canadian PR had stated the wrong birth dates for my parents in his PR application.
For my parents' subsequent TRV applications, TRV Invitation Letter, and other related documents, we specified the correct date of births. In any case, my parents' passports have the correct DOB. There was no problem for their TRVs.
Later, we sent all appropriate documentation to CIC to inform them about this mistake in the PR application
Hope this helps. All the best