Submitted by: @pavel-zotov

Steps to reproduce:
1) Create following script (correct path and name of test DB to your env.):

set bail on;
set names utf8;
shell del c:\temp\tmp4test.fdb 2>nul;
create database 'localhost:c:\temp\tmp4test.fdb' user 'SYSDBA' password 'masterkey'; -- default character set utf8;
create role fo;
commit;
set heading off;
select 'Completed.' from rdb$database;
show version;

2) Apply it:

C:\FBTESTING\qa\fbt-repo\tmp>C:\FB\40SS\isql -q -i test-role-utf8.sql

Completed.

ISQL Version: WI-T4.0.0.1694 Firebird 4.0 Beta 1
Server version:
Firebird/Windows/AMD/Intel/x64 (access method), version "WI-T4.0.0.1694 Firebird 4.0 Beta 1"
Firebird/Windows/AMD/Intel/x64 (remote server), version "WI-T4.0.0.1694 Firebird 4.0 Beta 1/tcp (Image-PC1)/P16"
Firebird/Windows/AMD/Intel/x64 (remote interface), version "WI-T4.0.0.1694 Firebird 4.0 Beta 1/tcp (Image-PC1)/P16"
on disk structure version 13.0

3) Try to extract metadata:

3.1) without specifying charset for connect:
C:\FB\40SS\isql -x localhost:c:\temp\tmp4test.fdb

Output:
---------
SET SQL DIALECT 3;
. . .
CREATE ROLE FO;

(i.e. all fine)

3.2) with specifying single-byte charset. I use win1251:
C:\FB\40SS\isql -x -ch win1251 localhost:c:\temp\tmp4test.fdb

Output: the same, all fine.
---------

3.3) with specifying UTF8:
C:\FB\40SS\isql -x -ch utf8 localhost:c:\temp\tmp4test.fdb

Output:
---------

SET SQL DIALECT 3;

/* CREATE DATABASE 'localhost:c:\temp\tmp4test.fdb' PAGE_SIZE 8192 DEFAULT CHARACTER SET NONE; */

COMMIT WORK;

/* Grant roles for this database */

/* Role: FO, Owner: SYSDBA */
CREATE ROLE FOStatement failed, SQLSTATE = 22001
arithmetic exception, numeric overflow, or string truncation
-string right truncation
-expected length 2, actual 8
;

No such error on WI-V3.0.5.33217.

PS.
Note: i intentionally did not use non-ascii role name (though when use it the error the same).

Commits: 57b0f8a 8a858aa