We have a problem when startdate of an event and enddate have different month, the event is saved with one day less.
In order to solve it, we have changed the line 169 of Eventitemizer.php, instead this:
$dayrange = new \DatePeriod(new \DateTime($date->format("Y-n-1")), $dayinterval, $this->event->getEndDate());
to this:
$dayrange = new \DatePeriod(new \DateTime($date->format("Y-n-1")), $dayinterval, new \DateTime($this->event->getEndDate()->format("Y-n-j 23:59:59")));
With that the problem is solved, is it wrong??