EDIT: I just realised you were correcting my typo for me not asking. sorry and thanks for correcting it. Ignore the granny sucking eggs below. I'm not deleting it though, because it's got a pretty drawing.
Pipes expand/contact as they heat and cool in an axial direction. when you have a bend like this the pipe coming in wants to push the bend (and thus the pipe round the corner) in that direction.
if you don't let it move, the expansion is restricted and the bend has to deform to allow for the movement.
you can get away with some of it if depending on the length of pipe between the constraints, I'm guessing here but I reckon the pipe hits a joist 10" after the bend (down on the first picture) and it's tight up against the notch wall that was cut for it. the inner pipe isn't and will be able to slide on the joist to allow the movement to be taken up by the pipework.
rubbish drawing but something like this.
- (2.55 KiB)
Carbon fibre is just corduroy for cars.