Yeah its pretty low priority (I guess it might be a bigger problem for users who read non-English fanfics). Just something to look at again if you need to change that bit of code again at some point.
EDIT: I did mess around with it a bit with some things I googled. Changing errors='strict' didn't work, neither did adding encoding='utf-8'. Commenting the line out to see what would happen caused FFF to fail to load at all.
This is why I am not a programmer.
ANOTHER EDIT: Although I couldnt fix it myself, I did file the bug on the Github mostly for documentation purposes.