Lock Due Date of Milestones

[ka_nishiyama]

It’s not set up exactly as requested.
However, I think it can be used in a similar way.

New! Edit restrictions on Assignee and Due Date fields

Hi Asana community! I’m excited to announce we just expanded edit restrictions to support Assignee and Due Date fields. This means you can now apply the same level of control to these core fields as you can with custom fields, limiting who can update task assignments and due dates to reduce accidental changes and improve governance. Whit this update you can: Prevent unauthorized changes to critical task information Limit who can modify assignments and deadlines …