Some related tables have Referential Integrity (RI) constraints enforced on them. For example, with OrderHeader and OrderLines one cannot have OrderLines without an associated OrderHeader.
When processing change events by the table (which is how SQL-based CDC works) as opposed to by transaction, referential integrity cannot be maintained properly. For example, when first handling all OrderHeader records and then all OrderLines records then a deleted OrderHeader may be applied long before the required delete of the associated OrderLines records.
In order to reduce the potential referential integrity to a known time frame after which referential integrity is restored, a somewhat different process is needed (compared with Reading the Change Tables’).