Some periods not taken into effect

Hello,

I have 2 different cases where events are not displaying correctly in the calendar (for custom class holidays):

1. December 23, 2016 – January 8, 2017 (event is displaying on calendar only for December 2016 and nothing in January 2017)

2. June 30, 2017 – August 27, 2017 (event is displaying on calendar only for the first day, January 30, and nothing for the other days).

Thanks.