Prerequisite of task group not triggering any violation

[lifepillar]

To reproduce:

1. Create new project and set Task 1 to manually start at T+2d.
2. Create Task 2.
3. Create another task and make it a child of Task 2 (becoming Task 2.1).
4. Set Task 2.1 to manually start at T+1d.
5. Create a Finish-Start dependency between Task 1 and Task 2 (which is a task group now).

I would expect step 5 to trigger a violation. Is this expected? Is so, what is the reason for no violation occurring?