The "Open for Time Entry" checkbox works only when selected from the classic UI, not in the new UI.
1. Open New UI Resource page
2. Select a resource
3. Click on an investment the resource is allocated to to open the 'Detail' tab
4. Tick "Open for Time Entry"
Expected result: The resource can log time against the project
Actual Result: The resource cannot log time against the project
The page in the 'Detail' tab that user opened goes to the Project - Team tab in PPM Classic and it is true that the Team Member is Open for Time.
However to ensure that a Project is Open for Time Entry, go to the Project DETAILS tab => SETTINGS
(at the bottom of the page).
THE 'Open For Time Entry' in the project 'SETTINGS' section determines whether or not a project is Open for Time Entry.