Problem understanding semaphore control and task priority

Hi, I am having three tasks, where task A has higher priority, task B has normal priority and Task C has lower priority.Task B has main task which decides to wake which task and get acknowledge from those tasks. My problem is when task A is waiting for some action to be done, at that time task c releases the semaphore for task A, task A is not waking up. Please anyone tell what could be the issue

Hello Hari, would you mind to attach the task code to your post? You can first ZIP it.