i create then save a dashbord with different tables etc.: I save it with the date on quick part: today
because i want each day have the dashboard of the today view
but when i call back the dashboard
it is opened according the date set on the discover page so it is nok at all
it is not a today view

It's expected that if you manually set a date in Discover and then navigate to Dashboard the time set in Discover is sticky.

However, if you reopen the dashboard with previously saved timeframe using the"Open" icon in Dashboard, it should load the previously saved timeframe, as long as you checked that box when saving the dashboard.