The after hours pattern seems to be nothing more significant than an interesting and entertaining anomoly.
Don't ever assume that GOL, or any other stock for that matter, "has to go up." One thing that bothers me is that the Brasil Bovespa has been very strong lately. At the same time, GOL has been dying. Brasil should be leading our market for their ADRs, but apparently there's a disconnect. The present fundamentals look favorable, but I'm always suspicious when any stock behaves in such an opposite manner. Pay more attention to the negatives, and focus on what might go wrong. A good example of that is when people flock to a particular stock because it pays an unusually high dividend. That's always a red flag for me. There is almost always a reason for that kind of anomoly, such as the dividend is not covered by earnings and will soon be cut. When a stock is weak and looks as if it should be strong, there's usually a good reason that just isn't apparent, YET.