In properties of Scalability Collect Task, all Tasks are in Available list. If we move them to Selected Tasks and save the modifications, they appear again in Available list
Client Automation 14.5 CU5
It is only a display issue. To make sure that all tasks are selected, select all the tasks from "Available Tasks" list and move them in "Selected Tasks" list.
Fix T5IZ470 resolves this problem. Open a case at CA Broadcom Technical Support to get this fix.