icloud calendar expanding scheduled date

Whenever I click to open an event that is scheduled for the entire day the event is automatically changed to 2 full days. For example, an event is schedule for all day (the box that reads All Day is checked) on Oct 16th...then I click on it and it is changed to Oct 16th 12am thru Oct 17th 12 am (and the All Day box is no longer checked). I don't know how to get it to stop doing this?

最后更新：2017-10-13 23:15:53