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.