The first problem was triangles with motion blur were all grouped into
one category without separating the ones with and without triangle
motion steps.
The second problem was HIP RT uses the generic motion triangle
intersection function and this function checks prim_visibility buffer.
HIP RT doesn't provide the buffer per primitive but passes it to HIP RT
core per instance.
The buffer name was changed to prim_visibility from visibility to be
the same as what Cycles uses but when the motion triangle intersection
function is called from HIP RT kernels, the instance id is passed to
the function instead of primitive id.
Pull Request: https://projects.blender.org/blender/blender/pulls/114555
13171183fa