Because they are doubting PA's eligibility, there is red flags or security issuesWhen do they transfer after assessing a eligibility of sponser.
Did the PA ever overstay in Canada or has a history of applying to immigrate to Canada before sponsorship?
How long have you been dating/know each other for before getting married/living common law?
May I ask what's the PA's country of origin?
Anything can be the reason and you gotta tell us so we can guide you