I asked Chuck Rogers(RASAero) Rogers Aeroscience, to see if he could sim your camera shroud and see if the transonic shock wave was throwing out the CP. The Camera shroud is in line with one of the fins. Certainly with the position and size of this shroud there is a possibility of this shockwave preventing one of your fins being seen by the airflow. Your video shows a wobble before break up at about the point it would have been in that speed region. As you go transonic, your dynamic forces increase dramatically. Also your camera shroud would be giving you quite a kick sideways at the point your airframe was approaching max load and perhaps shielding one of your fins on a longer than normal airframe.
Catching up on Rocketry Forum posts. Had problems with my primary computer, had to use various back-up computers including an iPhone and I got behind on e-mails and reading Rocketry Forum posts.
I quickly went through all the posts. From the preflight simulation, at the failure point at 2.5 seconds, what was the Mach number?
Norm has sent me some shroud geometry data, which I'll take a look at.
Some possible additional effects to those previously discussed:
1) The side area of the camera shroud added CNalpha up at the front of the rocket, moving the CP forward. RASAero II accurately predicts the drag of the shroud, but currently does not predict the CNalpha of the shroud. But the CNalpha from the shroud did move the rocket CP forward. The camera shroud was somewhat large compared to the diameter of the rocket.
2) With the drag of the camera shroud, the rocket flew at a small non-zero angle of attack. This small non-zero angle of attack also moved the CP forward.
Combine 1) and 2) above, and there was a forward movement of the CP, which may have been significant.
Again, RASAero II accurately predicts the drag of the camera shroud. You can run RASAero II with and without the camera shroud, look at the Drag Force output in the Flight Simulation plots, and the difference will be the drag of the camera shroud, which can be quite significant when the camera shroud height above the body tube is a significant fraction of the body tube diameter.
Charles E. (Chuck) Rogers