When runtime column propagation (RCP) is enabled, a schema file is required in certain stages to define the metadata for columns. The Column Import stage requires a schema file because it uses the schema to import the necessary metadata about the columns being processed. The Make Subrecord stage also requires a schema file because it deals with creating subrecord structures based on the defined schema. Therefore, the stages that require a schema file when RCP is enabled are Column Import and Make Subrecord.