Wall Layers References & Dimension Qs

Morning,
Quick one hopefully been trying to understand the Wall Layer References Node,
For the most part in a quick test it works but i have one wall that i cant get it to correctly dimension on.
I’ve rebuilt the wall (from a totally different wall type) and it behaves correctly however was hoping to understand why it would not work from the original wall.
Thanks
KS
240808_WallLayerDimsQS.dyn (56.9 KB)
WallLayerDimensionQs.rvt (652 KB)


Sorry to bump this but has anyone got any ideas?
Cheers
KS