I have compression fittings. When using indigo xtreme TIM which becomes liquid around 70C, you turn the pump off, and load the cpu, have to heat the waterblock to about 70+C to make indigo metal turn liquid, so it will reflow. If the waterblock does not get that hot it will not reflow. I have done this 3x for 3 different indigo applications. And when water is not flowing, the waterblock will get to 70+C quickly, since no cooling at all is taking place since no flow. With water flowing, it would never get that hot, even with cpu 100C. Throttling keeps the cpu temps at 100C or below, and when thottling fails, thermatrip shutsdown the computer.
But no tubes pop off the compression fittings, nor would I expect them too.
Good to hear that the tubes didn't pop off on yours. Mine did however , I guess it's different strokes for different folks.