The Connector Temp folder is filling up during ingestion, using too much disk space.
The typical process flow for a connector is for it to download the file to a temp directory (e.g. SharePoint Remote Connector\Temp) and pass that to the Connector Framework (CFS).
Once the CFS has finished processing the file, CFS will delete it - not the connector.
Ensure that the Connector Framework service and the Connector are configured to use the same service account and that account has full rights to the Connector's Temp location.
Assuming the permissions are correct and the CFS account has Full control of the Connector Temp location, then this may be due to a performance bottleneck or a problem with CFS indexing to the IDOL Server.