Orchestration Error: The value of the attribute Field Update JSON isn't valid.

HI team,

We've tried to create an Orchestration for the Sales leads. While we're trying to Validate, we're receiving the following error.

We've not used Field Update as a task or Action in this Orchestration.

When we click on the error, it is redirecting to the particular area where we have the issue. Please find below screenshots of configuration.