When viewing calendar on Android (Unsure about iOS) and new all day events are displayed, the view in week view pushes all hourly events down to provide space for the all day events pane on top.

It can be rather bumpy when going between weeks, as the hourly events keeps being pushed up and down in the view.

Suggestion would be the same as done in Google Calendar (Not sure if other calendars are the same), where all day events still get displayed, but it "overlaps" the top of the calendar more or less adjusting to how many all day events are displayed. This keeps the hourly events in the same position as displayed when scrolling between weeks. Much easier on the eyes.