After the side load I tested the in plane bending (trying to pull the joint apart in the the plane of the frame). I used split blocks to support the ends of the tube and a 4' solid steel pry bar to apply the load.
I applied almost 1/2 my body weight to the joint about 4 feet from the support block. So, the joint was under 300+ ft-lb of torque. After alternating this load in opposite direction a few times there was a cracking sound and this small flap of carbon pulled free. Also, a small crack curved under and along the joint fillet..
One good hard heave (probably over 400 ft-lb) and the joint cracked further.
Eventually if failed completely...