Issue with calendar view. Missing tasks.

I have been testing Producteev for several months now but recently I noticed a very problematic bug.

Some tasks are not showing in the calendar view - this seems to be happening mostly for the first day in the monthly or weekly view.

Example 1:

Screenshot 1 (blue box) shows no items for 2017/04/24 in a weekly view but a switch to the monthly view (screenshot 2, blue box) show one task.

Example 2:

Screenshot 3 (orange box) shows no items for 2017/05/01 in a monthly view for May but switch to April (screenshot 2, orange box) reveals 3 items for that day.

Screenshot 1

Screenshot 2

Screenshot 3

Did anyone have similar problems?

Thank you in advance.