Alert panel resent state changes not display when timerange is "today"

Problem:
I placed an alert panel on a dashboard and set the dashboard timerange to “today”.
There were no resent alert changes displayed in the panel.
If I set the dashboard timerange to " 00.00.00 to 23:59:59",
resent alert changes items are displayed.
I think the timerange “today” filter doesn’t works.

Any idea ?