Hey there,
in case you entered keywords that should highlighted in chat containing umlauts or other special characters, then backup/export your BTTV settings, the umlauts and special characters are saved as "�".
In my case I want to highlight the German word "fußball" (football). The exported json (.backup) file has the value "fu�ball". This is the case with German umlauts like ä, ü, ö as well.