Mysql InnoDB Cluster - Router - Pre-auth socket failure x.x.x.x:x: client auth timed out

[setra user]

Hello,

We had a problem with our MySQL Router:

INFO [7f0e8b2f9700] [routing:moncluster_default_rw] fd=19 Pre-auth socket failure x.x.x.x:x: client auth timed out
INFO [7f0e8b2f9700] [routing:moncluster_default_rw] 97 connection errors for x.x.x.x:x(max 100)

When the counter get to 100, the router gets stuck for security reasons.
We have to restart it to make the service.

There are no error in the log of data nodes.

We not understand, why we have this error. The client send this password correctly, but this problem still happens at the same hours...

Other informations:

mysql> select @@version;
+-----------+
| @@version |
+-----------+
| 8.0.13 |
+-----------+

user@router:~$ mysqlrouter --version
MySQL Router v8.0.13 on Linux (64-bit) (MySQL Community Server - GPL)

Architecture :

3 data nodes
2 routers

mysql> show global variables like '%time%out%';
+------------------------------------------------+----------+
| Variable_name | Value |
+------------------------------------------------+----------+
| connect_timeout | 10 |
| delayed_insert_timeout | 300 |
| group_replication_components_stop_timeout | 31536000 |
| group_replication_member_expel_timeout | 0 |
| group_replication_unreachable_majority_timeout | 0 |
| have_statement_timeout | YES |
| innodb_flush_log_at_timeout | 1 |
| innodb_lock_wait_timeout | 50 |
| innodb_rollback_on_timeout | OFF |
| interactive_timeout | 28800 |
| lock_wait_timeout | 31536000 |
| mysqlx_connect_timeout | 30 |
| mysqlx_idle_worker_thread_timeout | 60 |
| mysqlx_interactive_timeout | 28800 |
| mysqlx_port_open_timeout | 0 |
| mysqlx_read_timeout | 30 |
| mysqlx_wait_timeout | 28800 |
| mysqlx_write_timeout | 60 |
| net_read_timeout | 30 |
| net_write_timeout | 60 |
| rpl_stop_slave_timeout | 31536000 |
| slave_net_timeout | 60 |
| wait_timeout | 28800 |
+------------------------------------------------+----------+

mysql> show full processlist;
+-----------+----------------------------+----------------------+--------------------+---------+----------+--------------------------------------------------------+-----------------------+
| Id | User | Host | db | Command | Time | State | Info |
+-----------+----------------------------+----------------------+--------------------+---------+----------+--------------------------------------------------------+-----------------------+
| 226670600 | unauthenticated user | x:y | NULL | Connect | 9 | login | NULL |
| 226670717 | unauthenticated user | x:z | NULL | Connect | 3 | login | NULL |
| 226670764 | unauthenticated user | x:a | NULL | Connect | 2 | login | NULL |
| 226670791 | unauthenticated user | x:e | NULL | Connect | 1 | Receiving from client | NULL |
+-----------+----------------------------+----------------------+--------------------+---------+----------+--------------------------------------------------------+-----------------------+