functions_phpbb20.php considers 3 different russian usernames to be colliding

Hello,

I'm using phpBB3-RC5 on OpenBSD-current (soon to be 4.2) and PostgreSQL 8.2.5 (installed from OpenBSD ports).

While trying to convert from my old installation phpBB2 (in WIN1251 encoding), I've got this error message at the final stage:

Fatal conversion error

functions_phpbb20.php [ 1876 ]

Colliding usernames were found on your old board. In order to complete the conversion please delete or rename these users so that there is only one user on your old board for each clean username.

p is the clean username for:
» user id: 245 username: Р (0 posts)
» user id: 347 username: Р (0 posts)
» user id: 657 username: Р (0 posts)

This is wrong: while all 3 users start with the same russian "I" letter, they have different usernames - I'm attaching the output of

select * from phpbb_users where user_id=245 or user_id=347 or user_id=657;

(with the e-mails changed for privacy reasons).

Regards
Alex