My moodle version is 2.0.1 (build 20101225). I am having an issue with the weekly format on created courses. I'll do my best to explain and have attached a screenshot.
1)weekly format is selected
2)some of the weeks are hidden
3)the weeks are collapsed to only see the main selected week
The jump to button lists all the hidden weeks as the same date. Also, if you choose a certain week and weeks later in the calendar are hidden, the jump to sends you to the wrong week.