I found a bug in FullCalendar getEvents() method. If I load events (and this is recurring event) and it falls on the last column (in week view), then Calendar::getEvents() return duplicated event on that day.
Here you can see in console: https://codepen.io/matthew_gates/pen/QWwdvMz?editors=1010
Array(3)
Does anyone else have such a problem?