Closing up this thread by saying that while the FastAI custom environment did not solve the issue, downgrading to PyTorch 0.3.1 did do the trick.
I had to do so via this version from peterjc123 because the typical conda install command didn’t work (anaconda didn’t have the 0.3.x packages anymore)
The command I used was:
conda install -c peterjc123 pytorch cuda80