Based on test patch 6846913c9fecb7d (server branch bb-10.5-anel-anonymous-user-windows-check ), we can see that anonymous user, when used with skip-resolve-name gets Adminstrator user as confermed on buildbot-windows.
I haven't checked localy, only on buildbot. I expect that when run locally, it should be the same output (with other USERNAME, see below) ?

• Test:
  Start server with skip-resolve-name (add option to file <mtr_file_name>-master.opt, create test case:

  create role test_role;

  grant test_role to ''@localhost;

  connect(con1,localhost,'',,,$MASTER_MYPORT); # here it fails on Windows only

  SELECT CURRENT_ROLE;

  SET role test_role;

  SELECT CURRENT_ROLE;

  # user cannot set subset role, since it is not granted explicitly

  --error ER_INVALID_ROLE

  SET role new_role;

  --error ER_PASSWORD_ANONYMOUS_USER

  set default role test_role for ''@localhost;

  connection default;

  disconnect con1;

  REVOKE all privileges, grant option from ''@localhost;

  --source include/delete_anonymous_users.inc

  drop role test_role;

• Output:

  main.anel w5 [ fail ]

  Test ended at 2023-01-27 16:26:18

  CURRENT_TEST: main.anel

  mysqltest: At line 10: query 'connect con1,localhost,'',,,$MASTER_MYPORT' failed: 1045: Access denied for user 'Administrator'@'::1' (using password: NO)

  The result from queries just before the failure was:

  # Verify anonymous user on Windows is not 'Administrator'

  #

  # Test of anonymous user connection

  --------------------------------------------------------------

  create role test_role;

  grant test_role to ''@localhost;

  - saving 'D:/Buildbot/amd64-windows/build/mysql-test/var/5/log/main.anel/' to 'D:/Buildbot/amd64-windows/build/mysql-test/var/log/main.anel/'

  Retrying test main.anel, attempt(2/3)...

• Note:
  It may be related to libmariadb client authentication here where USERNAME is read instead of mysql->user, for which mysql->user[0]=''.
  It occurs only when skip-name-resolve is used (not sure why?) and only on Windows because of function read_user_name implementation on Windows, that is using USERNAME.