Strange behavior of list, tree and grouped sorting (tasks) / #1472

I hope I can explain the situation.

In general I have the role of an admin at Streber.
And normally I'm not related to a project or a task.

Scenarios:

1. Project with 1 task
   • List: 1 task
   • Tree: 1 task
   • Grouped: 1 task
2. Project with 5 tasks
   • List: 5 tasks
   • Tree: nothing
   • Grouped: 5 tasks
3. Project with 4 tasks and 1 task related to a milestone
   • List: 4 tasks and 1 task related to the milestone
   • Tree: only the task related to a milestone
   • Grouped: 4 tasks and 1 task related to the milestone

In these scenarios I'm not related to one of the projects or tasks.

• Project with 2 tasks (I'm related to one task)
  • List: 2 tasks
  • Tree: 2 tasks
  • Grouped: 2 tasks

So, you see the whole problem is really strange.