A record locking error normally indicates concurrent update contention: two or more transactions are trying to modify the same Salesforce record, or related locked records, at the same time. During a Data Mapper Load, this can happen when multiple users, automations, batch jobs, integrations, or OmniStudio processes attempt to update the same parent or child record concurrently. It is not primarily a field-level security issue; permission failures produce authorization errors. It also does not automatically mean the record is being archived or that the object batch size has been exceeded. The fix is usually architectural: reduce concurrent writes to the same record, serialize critical updates, review automation on the object, and avoid unnecessary parent-record updates. Salesforce documents UNABLE_TO_LOCK_ROW style behavior as a concurrent update/record lock problem.