We're using Transformation Spec feature of the bulk api when uploading records:
https://developer.salesforce.com/docs/atlas.en-us.api_asynch.meta/api_asynch/asynch_api_mapping.htm
This allows us to map Csv Headers to Salesforce Fields without changing the file. However, there is an undocumented limit of 4000 bytes for the Transformation Spec. Due to this length limit, users can't import the necessary number of columns in the file.
Can we work around this?
Can we document this?
Can we increase this?