Lifecycle Stage Colors are not displayed for documents in Vault
If the Default Security of the Lifecycle State Stage ID and Lifecycle Stage fields are set to Hidden, a user (irrespective of the role) cannot see the value, which means the user cannot stage the colors of the stage grey bar.
To see the lifecycle stage color, the Default Security of these fields should be changed to Read Only. If the lifecycle stage color is still not displayed for documents, please open a support ticket.
Vault Help Documentation: