Some customer complains the object CUST_MAT_INFO cannot be loaded successfully from ERP to CRM.
If you are also facing the issue, please check the settings as below.
1> In ERP system, check if the the events in TBE31 for download object CUST_MAT_INFO as described in note 758622 are activated.
00504001 BC-MID CRS_CUST_MAT_COLLECT_DATA_CRE
00504002 BC-MID CRS_CUST_MAT_COLLECT_DATA_CHA
00504003 BC-MID CRS_CUST_MAT_COLLECT_DATA_DEL
2> In ERP system, check whether 'CRM_FILTERING_ACTIVE' is maintained for object CUST_MAT_INFO in the table CRMPAROLTP.
3> In CRM/ERP system, make sure the entries maintained as mentioned in note 787589.
4> In CRM sytem, if you check the parent object for CUST_MAT_INFO in R3AC1, you will find there are 3 entries:
BUPA_MAIN
MATERIAL
DNL_PLANT
These entries are basically present in DB table SMOFOBJPAR.
Instead of BUPA_MAIN, the parent object should be CUSTOMER_MAIN as per note 711254 states.
Please implement the corrections then run initial load of CUSTOMER_MAIN.

Also, the other two parent objects MATERIAL, DNL_PLANT should also be initial loaded sucessfully before you retest the load of object CUST_MAT_INFO.