All Mandatory Classification Values message when changing project status to Submitted with Workflow

Hi,

I am facing an issue when changing a project status from Unapproved to Submitted with Workflow enabled.

I have setup the Submitted status with Workflow enabled so the a notification goes to an approved that will approve the project.

But when the employee that sends the project for approval changes the status to 'Submitted' the system doesn't allow the status change and it display a message saying that all the mandatory classifications needs to be populated with a value.

However, I don't have any classifications setup as mandatory for the project type and template?

Any ideas why is this occurring?