The diff itself:
I'm not sure if the first check is needed.

*** mantis-0.19.2/account_update.php Tue Nov 30 15:02:58 2004
--- mymantis/account_update.php Mon Jan 17 18:38:06 2005

* 32,37 **
--- 32,38 ----
$f_password = gpc_get_string( 'password', '' );
$f_password_confirm = gpc_get_string( 'password_confirm', '' );

• if (OFF == config_get( 'use_ldap_email' ) )
  $f_email = email_append_domain( $f_email );

  # get the user id once, so that if we decide in the future to enable this for

  ---

  * 47,53 **

  @@@ Listing what fields were updated is not standard behaviour of Mantis

  #     it also complicates the code.

! if ( $f_email != user_get_email( $t_user_id ) ) {
user_set_email( $t_user_id, $f_email );
$t_email_updated = true;
}
--- 48,54 ----

@@@ Listing what fields were updated is not standard behaviour of Mantis

    #     it also complicates the code.

! if ( $f_email != user_get_email( $t_user_id ) && OFF == config_get( 'use_ldap_email' ) ) {
user_set_email( $t_user_id, $f_email );
$t_email_updated = true;
}

Thanks for the patch andri, it helped me to debug my Mantis installation.
Why isn't this patch included in the official Mantis release ?

As part of this fix we should fix the following 3 scenarios work:

1. An admin creating an account.
2. A user signing up.
3. My Account modifications.