For the % Complete Calculation Method of Effort, non labor resources are not included in the calculations. In order for the task % Complete and Statuses to be able to changed, the project % complete calculation method would need to be Duration or Manual. Note: It is not recommended to change a % Complete Calculation Method of a project once it's been set as this can impact the task data.
Note: Even if the % Complete Calculation Method of the project is set to Manual, in order to be able to save a task status of Completed, there must be 0 ETCs on the task. See KB000103580
for an error you can see on the Gantt when trying to update a task with ETCs greater than 0.