Copying activity StartTime using message scenario

Hi Team,

I have to copy the out of the box start time to a custom property to meet one of our requirements.

The following is the subject and body for my 'Set Property' message scenario

Subject - act_custom_start_time

Body - {activity_start_time}

Though activity start time is a DateTime field in UI and API response, only the 'time' part of it is getting copied into my custom property. For example , If the OOTB start time is "2024-01-02 10:24:00" , my custom property will have the value "10:24" . This is not what I am looking for. I need the DateTime value itself to be populated in my custom field. Also, I cannot append 'date' field in the body as we allow 24 hours overtime after midnight in Business Rule settings and hence the date can be sometimes different .