We are currently facing with this error (V1 427 item does not match schedule line (program error) in sap), when we open the sales order(VA02/03).
The error is occurring due inconsistency on the database tables, some Item is in table VBEP, but it is missing from table VBAP. This is what is causing the error message.
I checked various related notes - 442831 , 401463 , 389687 etc . These are quite old notes and I am in release ECC 6.0 .
Report SD_CONSISTENT_CHECK_EXT and SD_CONSISTENT_CHECK are already available.
Bapi BAPI_SD_SALES is also active.
Please let me know if anybody has any idea on the same.