Process Instances are getting deleted automatically after 30 days even though the Job "Delete Process Instance" is not scheduled.
All Clarity Supported Releases
The reason Process Instances are getting deleted because, there is job "Delete Process Instance - DO NOT MODIFY" that is scheduled by default with the below parameters
This job is scheduled by default to ensure process instances are deleted for past 30 days, however if you want to control the data based on your need you can follow the below steps