One limitation of Multi-threading for CSV imports in NetSuite is that "The order in which CSV file rows are submitted cannot be predicted." When multi-threading is enabled for CSV imports, NetSuite processes multiple rows of the CSV file in parallel to speed up the import process. However, this parallel processing means that the rows are not processed in the sequential order they appear in the CSV file. This can be a significant limitation when the order of row processing is crucial, such as when there are dependencies between the records being imported. Understanding this limitation is important for planning CSV imports that require a specific sequence of record creation or updates.References: NetSuite Help Center, CSV Import Guide.