I've not found a lot about spinal problems (I read that Steve had one with a kink spine, Bethan isn't nearly as bad as Steve's photo), but I expect a few people will have some experience.

Our smallest checkered seems to have a problem with her spine. About 2/3's of the way down her length there's a lump on her spine and her back seems to bend slightly there. Then another 1.5cm down there is another lump. The lumps are small but clearly visible and feel hard.
As she moves she doesn't move as fluidly as our others, most of her movement is driven from her upper body. The lower part has movement, but she doesn't have strength there to support herself. When she slithers her tail twists over then as she moves forward it comes back the right way up. She definitely moves slower and more awkwardly than her sisters.
Kind of worried about her as she hasn't eaten for 3 weeks now, and wasn't a good eater in the first place. She's also the one that had bad problems shedding.

I'm thinking there's some sort of spinal abnormality that has become more visible as she's grown. If she's not eating because she's got a bad back it doesn't bode well. I'm willing to try a live fish with Bethan, she's lovely to handle and I don't want to give up on her.