I downloaded the sample files and test script and everything worked fine for me.
But i did notice that the BimorphNodes package you have differs from mine. There could be something funny happening because of that.
I have BimorphNodes 5.1.2 installed currently with my Revit 2020.2.9 build.
I the ray bounce for me hit the underside of the slabs and structural beams for both levels tested as intended.
Sorry i couldn’t help more.