"OSError: [WinError 6] The handle is invalid" when importing arviz

I am trying to install arviz (within a conda environment) and use it within an rmarkdown file. It installs fine, but gives an error when I import it: OSError: [WinError 6] The handle is invalid (see below for details). The package is stored on a shared drive.

Could this be because the arviz filename (returned using py_discover_config) is incorrect? I think it should end with .py not .p (\GFS\myusername$\Profile\appdata\Python\Python36\site-packages\arviz_init_.p)

> conda_install("testpymc3", "arviz")
> py_discover_config(required_module = "arviz")
python:         C:/ProgramData/Anaconda3/envs/testpymc3/python.exe
libpython:      C:/ProgramData/Anaconda3/envs/testpymc3/python36.dll
pythonhome:     C:\PROGRA~3\ANACON~1\envs\TESTPY~1
version:        3.6.6 |Anaconda, Inc.| (default, Jun 28 2018, 11:27:44) [MSC v.1900 64 bit (AMD64)]
Architecture:   64bit
numpy:          C:\PROGRA~3\ANACON~1\envs\TESTPY~1\lib\site-packages\numpy
numpy_version:  1.15.4
arviz:          \\GFS\myusername$\Profile\appdata\Python\Python36\site-packages\arviz\__init__.p

NOTE: Python version was forced by RETICULATE_PYTHON
> import("arviz")
Error in py_module_import(module, convert = convert) : 
  OSError: [WinError 6] The handle is invalid

Detailed traceback: 
  File "\\GFS\myusername$\Profile\appdata\Python\Python36\site-packages\arviz\__init__.py", line 25, in <module>
    from .plots import *
  File "\\GFS\myusername$\Profile\appdata\Python\Python36\site-packages\arviz\plots\__init__.py", line 14, in <module>
    from .ppcplot import plot_ppc
  File "\\GFS\myusername$\Profile\appdata\Python\Python36\site-packages\arviz\plots\ppcplot.py", line 6, in <module>
    from matplotlib import animation
  File "C:\PROGRA~3\ANACON~1\envs\TESTPY~1\lib\site-packages\matplotlib\animation.py", line 625, in <module>
    class FFMpegWriter(FFMpegBase, MovieWriter):
  File "C:\PROGRA~3\ANACON~1\envs\TESTPY~1\lib\site-packages\matplotlib\animation.py", line 120, in wrapper
    if writerClass.isAvailable():
  File "C:\PROGRA~3\ANACON~1\envs\TESTPY~1\lib\site-packages\matplotlib\animation.py", line 620, in isAvailable
    stdout=subprocess.DEVNULL, stderr=subprocess.PIPE).stderr)
  File "C:\PR

Possibly related to this bug: https://github.com/KrishnaswamyLab/MAGIC/issues/148

Start with py_discover_config(required_module = "arviz") and the import traceback, especially the Python discovery path and matplotlib's animation.py subprocess call. Reproduce the reported conda, Windows, shared-drive setup; done means importing arviz from the R Markdown workflow no longer raises WinError 6 and the discovered module path is correct.