Calendar events disappear

I have a strong suspicion that this is another bug.

For some events in my calendar, it seems that a certain combination of locale and timezone makes them disappear.

The screenshots best explain the problem, because it could be hard to reproduce.

As you can see, when the locale is norwegian and timezone is set to the african timezone the event is not displayed. The event is also missing when setting timezone to UTC. I have not tried other timezones.
The timezone was set with

Calendar calendarComponent;

The second pair of screenshots indicate that when locale is set to english, the event is shown regardless of timezone.

I am running latest Vaadin. Version 6.4.5.