Bug #119247 Test main.log_buffered-big failure

Description:
Looks different from bug 103338. On a debug but not release build, somewhat intermittently:

[ 50%] main.log_buffered-big                     [ fail ]
        Test ended at 2025-10-27 18:06:14

CURRENT_TEST: main.log_buffered-big
WARNING: MYSQL_OPT_RECONNECT is deprecated and will be removed in a future version.
WARNING: MYSQL_OPT_RECONNECT is deprecated and will be removed in a future version.
WARNING: MYSQL_OPT_RECONNECT is deprecated and will be removed in a future version.
--- /Users/laurynas/vilniusdb/mysql-8.0.44/mysql-test/r/log_buffered-big.result	2025-10-23 17:10:18
+++ /Users/laurynas/vilniusdb/mysql-8.0.44/_build-debug/mysql-test/var/log/log_buffered-big.reject	2025-10-27 19:06:14
@@ -8,7 +8,185 @@
 [ PASS ] Successfully read JSON log file.
 [ PASS ] Error log successfully parsed as a JSON document.
 [ PASS ] Lines were converted from JSON to trad.
-[ PASS ] Traditional log and JSON-converted-to-trad log are the same.
+[ FAIL ] Traditional log and JSON-converted-to-trad log are NOT the same.
+
+--- Contents of converted file, /tmp/mtr-u0NO/buffered1.converted.err ---
+2025-10-27T16:06:13.072723Z 0 [Warning] [MY-013711] [Server] Manifest file '/Users/laurynas/vilniusdb/mysql-8.0.44/_build-debug/runtime_output_directory/mysqld.my' is not read-only. For better security, please make sure that the file is read-only.
...
+2025-10-27T16:06:14.179468Z 0 [System] [MY-010931] [Server] /Users/laurynas/vilniusdb/mysql-8.0.44/_build-debug/runtime_output_directory/mysqld: ready for connections. Version: '8.0.44-debug'  socket: '/tmp/mtr-u0NO/mysqld.1.sock'  port: 13000  Source distribution.
+--- end of inserted log ---
+
 RESET PERSIST log_error_services;
 RESET PERSIST log_error_suppression_list;
 SET GLOBAL log_error_services=DEFAULT;

mysqltest: Result length mismatch

The result from queries just before the failure was:
2025-10-27T16:06:14.072042Z 0 [Note] [MY-010264] [Server]   - '::' resolves to '::';
2025-10-27T16:06:14.072061Z 0 [Note] [MY-010251] [Server] Server socket created on IP: '::'.
2025-10-27T16:06:14.080022Z 0 [Warning] [MY-000067] [Server] unknown variable 'loose-mysqlx-ssl=DISABLED'.
2025-10-27T16:06:14.169938Z 0 [Note] [MY-011025] [Repl] Failed to start replica threads for channel ''.
2025-10-27T16:06:14.178501Z 5 [Note] [MY-010051] [Server] Event Scheduler: scheduler thread started with id 5
2025-10-27T16:06:14.178810Z 0 [Note] [MY-011240] [Server] Plugin mysqlx reported: 'Using SSL configuration from MySQL Server'
2025-10-27T16:06:14.179229Z 0 [Note] [MY-011243] [Server] Plugin mysqlx reported: 'Using OpenSSL for TLS connections'
2025-10-27T16:06:14.179259Z 0 [Note] [MY-011245] [Server] Plugin mysqlx reported: 'Scheduler 'network', post task'
2025-10-27T16:06:14.179276Z 0 [Note] [MY-011245] [Server] Plugin mysqlx reported: 'Scheduler 'network', create threads'
2025-10-27T16:06:14.179318Z 0 [Note] [MY-011245] [Server] Plugin mysqlx reported: 'Scheduler 'network', post task'
2025-10-27T16:06:14.179334Z 0 [Note] [MY-011245] [Server] Plugin mysqlx reported: 'Scheduler 'network', create threads'
2025-10-27T16:06:14.179324Z 0 [Note] [MY-011245] [Server] Plugin mysqlx reported: 'Socket_acceptors_task::pre_loop'
2025-10-27T16:06:14.179400Z 0 [System] [MY-011323] [Server] X Plugin ready for connections. Bind-address: '::' port: 13020, socket: /tmp/mtr-u0NO/mysqlx.1.sock
2025-10-27T16:06:14.179468Z 0 [System] [MY-010931] [Server] /Users/laurynas/vilniusdb/mysql-8.0.44/_build-debug/runtime_output_directory/mysqld: ready for connections. Version: '8.0.44-debug'  socket: '/tmp/mtr-u0NO/mysqld.1.sock'  port: 13000  Source distribution.
--- end of inserted log ---

RESET PERSIST log_error_services;
RESET PERSIST log_error_suppression_list;
SET GLOBAL log_error_services=DEFAULT;
SET GLOBAL log_error_suppression_list=DEFAULT;
safe_process[33585]: Child process: 33586, exit: 1

 - the logfile can be found in '/Users/laurynas/vilniusdb/mysql-8.0.44/_build-debug/mysql-test/var/log/main.log_buffered-big/log_buffered-big.log'

[100%] shutdown_report                           [ pass ]
------------------------------------------------------------------------------
The servers were restarted 0 times
The servers were reinitialized 0 times
Spent 0.000 of 22 seconds executing testcases

Completed: Failed 1/2 tests, 50.00% were successful.

Failing test(s): main.log_buffered-big

The log files in var/log may give you some hint of what went wrong.

If you want to report this error, please read first the documentation
at http://dev.mysql.com/doc/mysql/en/mysql-test-suite.html

mysql-test-run: *** ERROR: there were failing test cases

How to repeat:
CMake options -DCMAKE_EXPORT_COMPILE_COMMANDS=ON -DFORCE_UNSUPPORTED_COMPILER=ON -DCMAKE_BUILD_TYPE=Debug -DWITH_DEBUG=ON -DMYSQL_MAINTAINER_MODE=ON -DWITH_SYSTEM_LIBS=ON -DWITH_NDBCLUSTER_STORAGE_ENGINE=OFF -DDOWNLOAD_BOOST=ON -DWITH_BOOST=(path) -DFORCE_COLORED_OUTPUT=ON -DCMAKE_CXX_FLAGS=-Wno-invalid-specialization -g -DCMAKE_CXX_FLAGS_DEBUG=-Wno-invalid-specialization -g -DCMAKE_CXX_FLAGS_RELEASE=-O2 -DNDEBUG -Wno-invalid-specialization -g

Full test log

Attachment: 119247.log (application/octet-stream, text), 24.38 KiB.

Same on 9.5.0

Same on 9.6.0