Yuppyy.. I am proud of myself. I found a bug. :)
SMF 2.0 (and i think 2.1)
I convert my forum from ISO (Turkish character) to UTF-8 two months ago. Thousands of members have password problems. Especially in the Turkish character members. (e.g. ülkü, çetin, öğretmen, ü ğ ş ç ö, etc.)
I finally solved the problem today. Here is the solution:
forum/sources/LogInOut.php
Select
if ($context['character_set'] == 'utf8'
change
if ($context['character_set'] == 'UTF-8'
I converted from English- US ISO 8859-1 to utf-8, do you think I need to do that, just in case someone has used some special character (though I can't perceive it)
It seems a legit bug indeed. Thank you for the report :)
This was fixed a while back!