Your not the only one!
I don't normally "do" the medical kit, but the Dialysis Tech was there when I was, & he "showed" me around the machine diagnostics!
It's waste pipe Dave!
It has to have maximum slope, where as the trunking is level, and it looks worse due to the angle, plus most of it would have been hidden, until I went back & cut most of it out & modded it a few days later.
It had to be "set" around the trunking, so it really looks bad, but is not that bad really TBH.