Any task created in any view also shows up in the others. I just tested it and it works fine for me.
Usually when you create a task via calendar view it will automatically be added in the first column in the board (unless you move it to a specific section).
Now if you say you cannot see the task in board view please check whether you have any filter on maybe?
Thanks Andrea, those tasks were in the first column of the board.
I have lots of colums so first one was out of screen.
Problem solved an lesson learned