Putting this here for posterity.
A possible fix (works on my system). Try the following:
1) Load up Better Vampires in SSEEdit (or Creation Kit)
2) Select the Effect Shader category, and find the following four records:
3) For each record, find the parameter 'Edge Effect - Fall Off' and change (right click > edit) it from 0.00 to 1.00 (technically any value above zero is fine)
4) Exit SSEEdit to automatically save the changes
This should fix the black spots issue and allow the feature to work as intended.