Can the ”actual start time” be set to any time?

[RyoyaFukuda]

Hi all.

What are the "actual start time" and "actual end time" of project tasks?
I have confirmed that I can change the date to any date, but when I try to change the time as well, it is set back to the original time.
For example, if I change the "Actual Start Time" from 16:30 to 9:00 in the image, the "Actual Start Time" is set back to 16:30 and the "Actual End Time" is set to 2023-12-29 09:30:00, which is only ahead of the "Actual duration".
What is the cause?

[Siddhesh Gawade]

Hello @RyoyaFukuda ,

Can you please in details section the "Allow dates outside schedule" field? 

If its false, it mean  a Project Task's Planned Start Date and End dates Date will not use hours outside of the Project schedule(Schedule from parent Project Record) and it is expected behaviour. 

So you need to set  'Allow dates outside schedule' to true, set your Planned start/end dates to dates outside of the schedule and the dates will not update to be 0 second duration.

See serviceNow Support article for more information: 

Project Task Planned end dates set outside of Project schedule update to match Planned start date va... 

Kindly mark the answer ✔️Correct or Helpful ✔️If it addresses your concern.

Regards,

Siddhesh