None of my 4.32 projects will open in 4.24 with raytracing

A bit of a wierd one. I have developed a few projects in 4.23.1 with the intention of raytracing the final result.

They will raytrace fine in 4.23.1 and I can create a new raytrace project in 4.24.1 so I know raytracing works there, but none of my 4.23.1 projects will utilize raytracing in 4.24.1 no matter what I do.

I have ensured that I have gone into project settings and enabled raytracing in 4.24.1, and I have deleted my old postprocessor and recreated it with all the raytracing features enabled, but my projects clearly are refusing to raytrace in 4.24.1 (although they open fine and the shaders have recompiled)

What is going on?