I create a reoccuring event and save. Then I go back into the first occurence of that eventto edit and edit the time say, but leave all other fields the same. I click update and it asks me to apply to this even only or all events. I choose one or the other, I have tried both, and either way it turns the reoccuring event into a non-reoccuring event. So I only see it on the list or calendar view once, and when I view the event itself I no longer see the view all events option. I go back into admin to view this event and see that all the recurrence info is still saved.
Here is a sample of an event that used to be reocurring, then after an update became not reoccuring. http://www.manitobathunder.net/event/test-event-again/