For a manager the blue team rollup is not showing/displaying a aggregate total value for a forecast field for example:
 

Example where  aggregate total value is displayed:

 

if at least one of your team members has an incomplete status "null" for their forecast call, you will not see the Team Rollup in blue in your own team rollup. See screenshot below for what a incomplete "null" forecast call looks like for a team member:


For additional information please also refer to the following article from the Clari help Center:
https://clari.zendesk.com/hc/en-us/articles/115003342208-Managers-and-Execs-Calling-Your-Number