How odd! Sorry for the trouble. I'm actually working on a new update to the tool that should hopefully fix a lot of issues and be easier to use, but for now if you open up renedit_functions and go to line 12, you may be able to fix this by replacing it with this.
editlog.write("\nTypo logged at "+ str(renpy.get_filename_line()) + ":\n" + str(_last_say_what) + "\n\n----------------------------\n")
This will make sure the _last_say_what will be written down as text in the event no one spoke last (usually if you're using something different to display text... but not going to discount it being a Ren'Py 8.0 issue!)