Journey task not getting assigned to a different manager despite setting vacation rules

Line manager 1 has some assigned tasks in a journey. The manager sets up a vacation rule via Worklist > Preferences > vacation period, so that the journey tasks can be re-assigned to Line manager 2, during the first manager's absence. However, the second manager is still not able to take action on the task even though it has been delegated to him as seen in the picture below.

Please advise why the delegation is not taking place as expected.