events in multiMonthYear not showing when starting on same day, bug?

Question

Im using fullcalendar.io to show a multimonthyear calendar, but I found what i think is a bug. When rendering events some are not showing. In my case I had three events that started on the same day, two of them last 4 days, while the last one only one day, and i don´t know why event 1 isnt showing. Is this a bug or am i doing something wrong

Calendar view:

Here is the codepen where i replicated the error:

https://codepen.io/miguelTTP/pen/BabpQrp

document.addEventListener('DOMContentLoaded', function() {
  var calendarEl = document.getElementById('calendar');

  var calendar = new FullCalendar.Calendar(calendarEl, {
    timeZone: 'UTC',
    firstDay: '1',
    initialView: 'multiMonthYear',
    multiMonthMaxColumns: 2,
    contentHeight:"auto",
    editable: false,
    events: [
      {
        title: 'event 1',
        start: '2024-01-15',
        end: '2024-01-20'
      },
      {
        title: 'event 2',
        start: '2024-01-15',
        end: '2024-01-20'
      },
      {
        title: 'event 3',
        start: '2024-01-15'
      }
    ]
  });

  calendar.render();
});

I tried just putting the essentials for it to work, tried, on event 3, putting end date. Also tried couple more things but they didnt work.