Events from the past can appear in iCal Upcoming Event when they are set up as "all day events".
How to reproduce:
create a page with iCal Upcoming events on it and link a calendar
create a Event which last "all day" -> make sure that this event was yesterday
go to calendar and refresh then you will see the event from yesterday
Please note that if you create a "all day" event from Monday to Thursday you will still at Friday with the date from Monday
What I expect:
The Event will not be displayed at the next day
What really happens:
The Event appears as upcoming event even if it is in the past