Tasks view does not list tasks from all selected lists.
My collection account contains two Caldav-Tasklists. In Evolution 3.28.2 when I click in the "Mail" view/window, on the right there is a "To Do" containing both calendar entries and "Tasks without Due date" from both task lists.
In the "Calender" view/window on the righr I see "Tasks" and there the elements of both lists are displayed.
The "Tasks" view displays on the right side both lists, letting me select or deselect a list. If both lists are selected, then on the right side only the tasks of one of the selected lists are selected. To be precise, only tasks from the first list I select are displayed. The displayed tasks is correct, if I choose only one of the both lists, or none task list, but if both lists are chosen, then on the right side I expect that tasks from both lists are displayed, not only from one list.