Grasshopper viewport display hang - nurbsSpheres vs mesh Spheres

I’m experiencing an abnormal hanging behavior when generating primitive nurbsSpheres in Grasshopper.
While the ‘profiler’ reports a 44ms calc time for the nurbsSpheres, there is a significatn hang-time (~10-sec+) before they are visually generated in the viewport (gh hangs during this time). meshSpheres do not exhibit this behavior. Nor do other primitives. While I suspected this could have been a gpuDriver issue, I’m curious if there’s some other GH issue here since only the nurbsSpheres seem to be exhibiting this behavior?

RH Version 6 SR14 (6.14.19098.19271, 04/08/2019)
gtx980 v 425.31 (4/11/2019)

ghSpheres|690x370 (6.8 KB)