Form returns Response has been truncated

Have a CSV file that I upload, it check to see if the product is already in the DB, if it is then it updates the buy price, if not then it inserts a new record.

This is done in a repeat.

Problem I am having is I am getting the response Response has been truncated after about 11,288 records. Am I missing something here or is there some form of limitations to this? I have about 20,000 products in the csv.