Lawrence,
Tube bending is a gray area. The part is 18" long and has a 90* bend, forming an elbow. T-6 is a hard condition, while T-0 is soft.
Our CNC benders have much power. So much so, that they'll deform the tube, including ripping it in half, to unacceptable defects. The T-6 condition is very hard to bend. The force is similar to a tensile test. We have the tubes annealed to T-0 to allow for bending. The print requires the T-6 condition. So...we buy with T-6, change it to T-0, and change it back to T-6.
The heat treatments of the tube are prior to welding. Yes, it looks as though the leak is within the tube itself, and not the weld. The bubbles are a fine mist. The weld looks fine, considering the tube is a filthy gray / black condition.
Keith