Calendar app doesn’t work properly

Every time I change phones, the calendar app doesn't work properly. The calendar backup is enabled in iCloud. So the problem is that I can't search for entries before the change. Even if I type anything into the search bar, it only shows entries added after the phone change. However, if I scroll back to the days before the change and click on any day, it shows the scheduled events, but the search doesn’t find them. Additionally, when I want to add a new event/activity to a day, it doesn't suggest the previously used event/activity names.

Anybody with the same problem?