OK, I found the issue — looks like these lines in wp_ultimate_csv_importer.php are the culprit:
174-186:
// Scandinavian characters
function smack_marks_scandiConverter($text){
$returnvalue="";
for($i=0;$i<strlen($text);$i++){
$smacker=hexdec(rawurlencode(substr($text, $i, 1)));
if($smacker<32||$smacker>1114111){
$returnvalue.=substr($text, $i, 1);
}else{
$returnvalue.="&#".$smacker.";";
}
}
return $returnvalue;
}
and:
394 $data_array['post_title'] = smack_marks_scandiConverter($data_array['post_title']);
395 $data_array['post_content'] = smack_marks_scandiConverter($data_array['post_content']);