I did not see this specific issue in prior posts.
First: WP 3.9.1, TEC 3.5.2, TEC Pro 3.5.2
I’ve created several series of recurring events. In almost all instances, the event that is the first in the series gives mixed signals about what is happening. When I select “edit single” for the first in the series, I see the “split off” warning panel and click OK. When I am editing the event details, it indicates that I am editing all occurrences of the event. When I save, only that instance has actually been edited, but the indicator in the Events lists still shows that the event is part of a recurring series. I get the results I want, but I don’t get any indication that I did.
I can “edit single” all subsequent occurrences in the series and the indicators are not ambiguous. I’m not looking for answers here, but am including my observations in hopes that it helps resolve the remaining problems with your recurrence implementation.