Task does not appear in a resource calendar between the planned start and planned finish dates
In general, a demand item is displayed in the resource calendar only if the planned effort for the demand item is greater than zero (0) in the current period.
Example
A task is created with the planned start date of 1-Jan-2020 and planned finish date of 31-Dec-2020, and the option for the task to appear in personal calendars and resource scheduling calendar is selected.
The project manager allocates 0 hours for the task in the months of July and August. The task will not appear in the personal calendar or resource scheduling calendar during those months, even though the months are between the planned start and finish dates of the task assignment.