Problem with proper encoding data from LDAP (Windows AD)

RT Users
1

After upgrade from 4.0.10 to 4.2.11 , returning users autenticated via
LDAP (with ExternalAuth plugin), now have wrong polish characters in
their names, oragnization etc.

I turned debug options and see something like this:

[27516] [Tue May 26 10:58:01 2015] [debug]: UPDATED user mkolbe: User
mkolbe: City changed from ‘Ostróda’ to ‘Ostróda’
(/usr/local/plugins/RT-Authen-ExternalAuth/lib/RT/Authen/ExternalAuth.pm:421)
[27516] [Tue May 26 10:58:01 2015] [debug]: UPDATED user mkolbe: User
mkolbe: Organization changed from ‘Dział IT’ to ‘DziaÅ� IT’
(/usr/local/plugins/RT-Authen-ExternalAuth/lib/RT/Authen/ExternalAuth.pm:421)

Then RT allow user to login but corrected data by hand is overwritten by
data from Windows AD with wrong characters.

Any hints for solving this?