I tend to keep Agenda opened on my Mac from one day to the next.
When on the next day I click on the “Today” view in the sidebar, Agenda shows me the notes from the previous date. I guess it might be because the actual date shown by the “Today” filter does not change automatically when Agenda is opened and the date changes.
At that point the filter is named “Today” and shows yesterday. Because it shows me yesterday, the view title suggests I might want to save this view titled “Today” as a new one, even though there is already a view called “Today” in the sidebar.
If I quit Agenda and relaunch it, in the sidebar the “Today” view has been renamed “Yesterday”. If I click on the little dot in the date navigation everything gets back to normal.
I don’t know what the correct behavior should be … but having a filter called “Today” showing yesterday’s notes is clearly inconsistent.