I recently encountered a simple issue while working in Microsoft Dynamics Project Service to automate the creation of Project Contracts, aka Orders. An Order that I had created with Flow was displaying a notification saying “This form can only be used for project-based records. Record is read only” and all of its fields were locked.
I did a little digging and found this notification is always present in Project Service when the Order Type (msdyn_ordertype) option set field is set to anything other than Work based, value 192350001. Create the Order record with this value, or update it, and it is good to go.
The Order Type field is also used by other Apps to restrict access to Orders of the wrong type, so be sure to populate it accordingly with your Flows.