Explanation/Reference:
When you add a new task to a schedule, it automatically is scheduled to start on the project's start date. As tasks are added to the schedule and connected to other tasks, the start times of tasks will change, and the last task to finish determines the project's finish date.
Reference:
https://support.microsoft.com/en-us/office/how-project-schedules-tasks-behind-the-scenesdf3431ab-8d8a-4047-a

Explanation/Reference:
The entity's calculation status must be OK, No Data, or System Change. You cannot lock an entity with Impacted calculation status.
Reference: https://docs.oracle.com/en/cloud/saas/financial-consolidation-cloud/agfcc/ locking_and_unlocking_entities.html