Dave/Michael,
I had doubt about this "hysteresis or macroscopic entropy". Though the installation is not old, but this phenomenon can be there to gradually throw the clamp off its original location. Incremental advancement in the direction of forced movement and "denial" to comeback fully to original position due to resistance or whatever may become reason over time to displace supports in the piping. But at the moment system is under operation. Line is cold and shrunk. So we can check this only during next shutdown. I shall consider axial stop.
Below is another view of the condition: