You are seeing processes running when the processes start condition is not met. Saving the task without making any changes is triggering the processes.
The processes will trigger successfully when a start condition is met on one of these processes. However, the processes will also trigger if there are any updates to the tasks. (They do not trigger when a task is created.) Updates tested include changing the open for time entry, key task, assignment resources, and ETCs on assignees. Any of these changes will trigger the processes to start irrespective of the start condition of the triggered processes.
Release : 15.9.1
Component : PROCESS MANAGEMENT
Beginning with Release 15.4, a Task or Project object process condition cannot include a virtual attribute or aggregated calculated attribute. These attributes are no longer available for users to select in the expression builder when defining a process condition.