I've got an error when using GPU render settings:
C4DtoA | 00:00:17 1713MB ERROR| [gpu] context invalid (1284: Variable not found (Details: Function "_rtContextValidate" caught exception: Variable "Unresolved reference to variable __pvt_geometry_group_object from _Z11closest_hitv" not found in scope))
But everything works fine when i'm using CPU as render settings.
We've had a similar issue fixed recently, which was related to polymesh volumes (Arnold Mesh Volume tag). Could you please confirm this error happens with volumes?