All day event visualized also on the next day

[piper]

I am using Thunderbird 60.8, Lightning 6.2.8, Exchange Calendar 5.0.0-alpha3.
Each time I create one "all day event" for the day X, the event is wrongly visualized also the day X+1 on the calendar.

[piper]

Additional remark: the issue is just in the Day view mode. Week, Multiweek and Month modes work as expected.

[mechanista]

Also a problem in Week, Multiweek and Month view if the all day event ends on the day before the the first day shown in the view. e.g. All day event on ending on a Sunday will also be shown on Monday next week in week view, assuming Monday is first day of week in locale.

[simonschmeisser]

I can confirm that