BP not updating in Customer Master data KNA1

Guys,

I am creating a BP in CRM 7.0. Once the BP is saved & created successfully entry is present in all CRM tables as well as in the ECC side.

But for few cases the Customer Master data Table KNA1, KNVV is not getting updated, i.e no value for the BP in KUNNR.

Any idea as to what should I be checking to resolve this ? Plesae share the config details.

Also do you know how the Customer Master data gets updated ? Is it from the BAdI's or the GenIL class for CL_CRM_BUIL for componenet BP ?

I checked the methods of this dedicated GenIL class in hope to find an RFC for updating KNA1 but not successful. Is the RFC call made in BAdI ?

Tough to replicate the scenario as wheneevr I do BP gets updated in SD. But sometimes in PROD it does not happen so.

Plesae share some light.