When applying a cladding preset to a new spline, it has hilariously applied itself to almost the complete inverse of where it should be. I was wondering if the suggestions in the official YT video on cladding might help, in the Expand Hierarchy section, but so far no.
The spline came from using the Create Shape from Edges function on layer CH-EXT-LapSiding-7IN_Lap Siding - 7", so I'm not sure if it might just be a generic issue with the spline to begin with.