TargetAccountExpiredPasswordProcessorTask runs every 12 hrs. The first cycle occurs when the appliance (i.e. tomcat) is started and thereafter every 12 hrs.
Assuming that the first cycle has started at 5 PM UTC, then the next cycle will be around 5 AM UTC next day and then again 5 PM UTC etc. If you have created an account at 7 AM UTC and the password expiration is set to 1 day, then the password rotation will happen at 5 PM UTC next day. This is because the cycle runs at fixed times (i.e. 5 AM UTC & 5 PM UTC) and so when the current day 5 PM cycle is run the password has not expired because only 10 hours have elapsed. When next day 5 AM cycle is run the password is not expired because only 22 hours have elapsed. So when 5 PM cycle is run , password has expired as 34 hours have elapsed and so the password will be updated.
This TargetAccountExpiredPasswordProcessorTask job can't be manually configured by the user.