alf5071h - this is all pure speculation without the data but....
If the aircraft were at, say, 15 deg nose up pitch attitude and approx zero AoA in the climb before the incident, and were to pitch up to 30 deg AoA instantaneously, that's 15 deg AoA. To achieve that with the controls would take a great deal of nose-up pitch command - in the absence of such a command the aircraft would naturally be very quick to return to the trim near-zero AoA value.
If you were applying nose down-pitch command, but the pitch attitude were not changing, then I would conclude that you were in a stabilised condition. This would actually imply that your AoA was more negative during the event than prior to it, even though your pitch attitude was more positive. The simplest explanation for that is a downdraft.
Now, to address the altitude change - the aircraft went from FL130 to FL180 in one minute. One of the first things I would check with the data would be your geometric altitude, not your pressure altitude; in a significant atmospheric disturbance, I'm not sure I trust pressure altitude to be consistent through the event. If the shear/gust/downdraft were also associated with a significant pressure gradient, some or all of the apparent altitude change might have been due to pressure, not altitude. You mention it was at night, so a geometric altitude variation would not be so apparent.
Those would be my initial comments; as I mentioned, there would be a lot going on you might not be aware of, and only looking at the FDR traces would really resolve some of it.