Old password cache (LDAP)

I have mail server connected to UCS via LDAP - dovecot. When I change user’s password, he is unable to login to UCS, but he can connect to mail server using both old and new password for about 1 hour. It’s not the issue of dovecot cache - doveadm auth cache flush / restarting dovecot doesn’t help.
Is there any cache on UCS? How can I flush it?