I am using:
VCI Driver: 4.0.875.0.
I believe I have determined my root issue.
I am using the C-API from Python 3.8 to control the device. In the C-API for the device handle, the .h files show the PHANDLE parameter to be a void*. I was using a ctypes.c_uint32. Upping this to ctypes_c_uint64 or more correctly using ctypes.c_void_p resolved the issue.
I do not know why the C-API used 32-bit pointers when running on 64-bit Windows 7 vs. 64-bit pointers when running on 64-bit Windows 10.