Unassigned subtasks will not show on parent assigned ticket when board filter as subtask

[Weeda Lostitmonton]

Hi there.

When I created an issue: ''a-123'' etc. and assigned it to APerson,

then created a child issue: "a-124"etc - not assigned,

When I am on the Board page and select 'Subtask' as a filter - APerson will not be able to see the "a-123" issue appearing on the board at all. 

When we assign a-124 (child issue) to APerson, they can then see the task on the board. when the filter is 'subtask

Can we change it that when filter is selected as 'subtaks' on Board page - it should show the assigned parent ticket as well eventhough the child issue is not assigned or assigned to other person.