master data check in sap bw ip

Hi expert,

when running planning function or do manual input in SAP BW IP, there is check if relevant dimensions are valid or invalid based on dimension master data. my questions:

(1) is there always checking for invalid or valid by master data for planning functions or manual input in sap bw ip?

(2) there are a few invalid dimension values existing in planning cube, how did those invalid records get into planning cube ?

Many Thanks