About API get list events in Calendar View getting All-day event

Hello there,
I have a question. Can anybody here show me the exact changelog for the Rest API list calendarView. I think there're some changes that I haven't catched.
For example. when I called this API last year, if there's an all-day event in 2020-12-28 and I set startDateTime 2020-12-29T00:00:00, that event wouldn't appear on the response.
But now, I create an all-day event in 2020-12-28. When I call this API and set startDateTime 2020-12-29T00:00:00, I'm still able to see this event on the response. Only when I call this API and set startDateTime 2020-12-29T00:00:01, I could not see this event anymore. (Screenshots below)
I'm sorry if my explanation for my problem is hard to understand.
Thank you for reading, any help would be appreciated.
Do you have any updates?