Error inserting 2000 records or more with CreatedDate

[congmingwudi]

I have the following recipe for creating Leads with a generated CreatedDate. This works fine for num_records < 2000. Over 2000 (which looks like where Snowfakery switches to using the Bulk API), fails to insert all rows with this error:

[01/26/23 22:42:50] Job 7505e00000RZbzyAAD finished with result: Row failure: 2000 Errors                                                                    
                    Downloaded results for batch 7515e00000VNdCrAAL                                                                                          

Error: Error on record with id 1: INVALID_FIELD:Failed to deserialize field at col 0. Due to, '2018-09-28' is not a valid value for the type 
xsd:dateTime:CreatedDate --

- object: Lead
  fields:
    CreatedDate:
      date_between:
        start_date: 2018-01-26
        end_date: today
    Firstname:
      fake: first_name
    Lastname:
      fake: last_name
    Email:
      fake: email
    Company:
      fake: company
    Phone:
      fake: phone_number
    MobilePhone:
      fake: phone_number
    Website:
      fake: url
    Status:
      random_choice:
        - Contacted
        - Opne
        - Qualfied
        - Unqualified
    LeadSource:
      random_choice:
        - Advertisement
        - Employee Referral
        - External Referral
        - Partner
        - Public Relations
        - Web
        - Other