At the moment (v3.8) each scheduled task is creating a new customer (with role background task as far as I can see). As we created over 4.000.000 customer accounts within a year of testing and development, the count of new customers in live system would be much much higher.
As this is somehow unnecessary, can you please consider to reuse only one system account for scheduled tasks? So it would be even possible to identify scheduled task requests and skip some parts of the request (for example statistics).