Extracted from a cube more records than in fact table. How is this posible?

Hello all. I think the following questions are for gurus 😊

Is there someone that can explain me why if I do an exportdata source from a cube to load data to another cube, the number of records extracted is bigger than the number of records in the fact table?

Second question, if I have two cubes feed from an ODS and both cubes are exactly the same (one is copy of the other one) and the update rules are the same. How is it possible that the same load (with same number of record extracted) is adding different number of record in each cube?

Any clues on this will be very appreciated.

Thanks a lot,

Alfonso.