I am pretty sure I over cooked it. I kept waiting for the mixture to look glossy but it was only ever partial so I wound up cooking it for 3 hours before deciding to just put it in the mold anyway and the soap doesn't hold together very well. I am leaving it in for a day but when I was pressing it into the mold it just felt like it wasn't forming a cohesive whole.
I've never tried hot process bar soap, but I'd expect that rather than "overcooking" you may have evaporated too much water. This could result in a clumpy mass without much cohesion.
immersion blender till it thickens up would be where you stop and pour in the mold. Cover it and wait for at least 24 hours before taking it out to dry