Time period which lasts less than 24h is displayed as one day date
This happens when we specify time period date which start in one day and end in 2nd but time between start and end is shorten (or equal) than 24h. For example, if we specify start as 24.04.2018 13:00 and end 25.04.2018 at 12:00 at the entry view will appear as 24.04.2018, if we change end time to 25.04.2018 13:01 then we will see at entry view both dates.
This affect very much situation when only date (without time) is selected in entry edit form, then when we set 24th to 25th it set in most cases same time for bot dates and in the result in the entry we will see only first date