Here is an error with some username: http://tools.wmflabs.org/quentinv57-tools/tools/sulinfo.php?username=%C8%9Aetcu+Mircea+Rare%C8%99 Your tool cannot provide results for this user.
This user, exists, and he has accounts on several wikipedias, including rowiki (home)
https://ro.wikipedia.org/wiki/Utilizator:%C8%9Aetcu_Mircea_Rare%C8%99 and commons
https://commons.wikimedia.org/wiki/User:%C8%9Aetcu_Mircea_Rare%C8%99
Seems problem is in first diacritic symbol
Version: unspecified
Severity: major