If it’s the same airline as the return flight, the airline might be checking to make sure you can return to Canada. Without a valid PR Card, they’re not supposed to allow you on the return flight. (If it’s not the same airline, we are not sure why they are doing this.)
We cannot comment on what a airline does with this data.
When you apply for a new PR Card, you are asked to consent to CBSA sharing your information with IRCC. If you agree, CBSA shares your entries into Canada with IRCC. IRCC uses this data plus stamps in your passport to try to figure out if you were where you said you were. If they are not sure, they will ask you for more proof that you were in Canada. If it comes down to what they believe versus what you say, your status could be investigated further.
Canada do not yet have exit visas so, at the moment, it is only entries shared with IRCC. Once exit visas are introduced (and they are coming, due to an agreement with the US), they will know more from CBSA, and will not have to request additional information.