With the plugin enabled, all entries show miscoded signs. They are probably unicode (utf-8) signs being treated as western (iso-8859-1) - they look like: å, ä, ö. I figured changing the input and output encoding options to iso-8859-1 and utf-8 respectively would be fine, but there was no difference, and neither did swapping them around.
Peeked in the plugin file but couldn't figure where to change anything and how.