User Configuration > Administrative Templates > Microsoft Project 2016 > Project Options > Interface > Show indicators and Option butons for
User
HKCU\software\policies\microsoft\office\16.0\ms project\options\interface
Specifies that the feedback triangle should appear in a corner of the Duration field or the Task Name field if you change a task's work, units, or duration. If you enable this setting, a feedback triangle is displayed in the corner of the Duration or Task Name field if the user changes the task's work, units, or duration. If you disable or do not configure this setting, the user's default setting is used.