Imscully, I had this issue with the latest version of pyTranscriber (1.5 I believe) as well. Version 1.4 works a lot better for me, so maybe look for that and give it a try.
I get this from time to time auto translating Chinese srt files.
This is apparently what happens when the source file that is being used is not in UTF-8 format. The original srt file needs to be converted using something like subtitletools.com file convert.
UTF-8 File convert link