If you insist on explaining Leia's memory of her mother, which is a futile exercise IMO, I would say that she remembers her adoptive Mother who, in her eyes, is her 'real mother'. It might even be that she doesn't know she was adopted so when Luke asks about her 'real mother' she has no reason to think of anyone except the woman who raised her. But that is stretching it - like I said, crap and full of holes.
If you insist on explaining Leia's memory of her mother, which is a futile exercise IMO, I would say that she remembers her adoptive Mother who, in her eyes, is her 'real mother'. It might even be that she doesn't know she was adopted so when Luke asks about her 'real mother' she has no reason to think of anyone except the woman who raised her. But that is stretching it - like I said, crap and full of holes.