BUG #19410: Cannot ser client_encoding

The following bug has been logged on the website:

Bug reference: 19410
Logged by: Guest-615695028
Email address: 615695028(at)qq(dot)com
PostgreSQL version: 18.1
Operating system: Microsoft Windows [版本 10.0.26200.7840]
Description:

PS C:\> psql -U postgres
Password for user postgres:

psql (18.1)
Type "help" for help.

postgres=# SHOW client_encoding;
client_encoding
-----------------
GBK
(1 row)

postgres=# SET client_encoding='UTF8';
SET
postgres=# SHOW client_encoding;
client_encoding
-----------------
UTF8
(1 row)

postgres=# \q
PS C:\> psql -U postgres
Password for user postgres:

psql (18.1)
Type "help" for help.

postgres=# SHOW client_encoding;
client_encoding
-----------------
GBK
(1 row)

postgres=#