Trying to automaticaly update time spent field but I get an error.

[isabel_p_cardoso_hotmail_com]

Can someone please help me if this case. I have created a variable that calculates end date - start date and gives me time spent on an issue, but when I try to update time spent field, I get this weird error: Worklog must not be null. Invalid time duration entered. (timeLogged).
But my worklog variable does have value, as you can see from the audit log below:

[Harrison Ponce]

Hi @isabel_p_cardoso_hotmail_com , I tried to test this out on my own and made this work with a simpler approach not needing variables. For me, using the Start Date and Due Date fields, I did the following:

WHEN: Value changes for due date / start date

THEN: Log work

• Time spent: {{due date.diff(start date).days.abs}}d
• Date started: {{now}}

Would that work for your use case (of course swapping out for the fields you're using?