Task Assignment may be Incorrectly Rejected

[NealSun96]

Describe the bug

Sometimes tasks may not be assigned even when there is quota available.

To Reproduce

Create two jobs, A and B. Assign job A task 1 and 2; assign job B task 1 and 3. After assigning the tasks for job A, it's possible that task 3 from job B doesn't get assigned even when there is quota available.

Expected behavior

Task 3 from job B should be assigned when there's quota available.