Using the 2017.2 Release functionality of People >> Planning >> Resource Planner, budgeting hours against a user does not automatically add that user to the project team.
Confusion is thus created when the PM is trying to assign tasks using the new functionality under Project >> Staffing >> Scheduling.
The user resources that were budgeted for the project, do not automatically appear on the Project team. Therefore, the PM must refer to a different report to identify which users were budgeted for that project. Or risk, using a user that was NOT budgeted for that project.