You have a Program with multiple tasks. On one of the tasks (projects) it shows 0% complete but when you look at that project all tasks are 100% complete.
% Complete for a project (Example Project A) on the Task list associated with a program is pulled from the project's % Complete value at the project level.
If you are using Effort or Duration % Complete Calculation Method, then the % Complete would be calculated based on the details listed at CA PPM Tuesday Tip: How do the three % Complete Calculation Methods Work.