This is currently working as designed. The new user experience currently only supports two levels of WBS. For any projects that have more than two task WBS levels, you will only be able to partially edit tasks in the new UX and some tasks may be missing if they are not the top or bottom level tasks in the WBS structure.
Some features that are available if using more than two levels of WBS include:
- Adding new assignments
- Changing a task status
- Changing a task name
Some features that are not available if using more than two levels of WBS include:
- Changing a task 'Start Date' or 'Finish Date'
- Changing 'Estimate to Complete' (ETC)
- Changing a task 'Type'
- Viewing tasks that are not at the top or bottom level in the WBS
Workaround: To work with more than two levels in a project, use the Gantt in the Classic (old) UI or one of the supported scheduler tools (Open Workbench (OWB) or Microsoft Project (MSP))