Oracle 12c on non-english windows hang with ORA-609 and TNS 12560

Hello,

I'm face to an issue that the MOS don't find solution since 13 days now.
My platform is Oracle server 12c on a French Windows Edition, but I believe it could concern also non english edition ... the reason of my post.

The issue :
After 2049 succesfull connexion, the database become unrecheable via the Listener, any attempt to connect after this 2049 connexion is hanging, But is still available via bequeath connexion (local with ORACLE_SID)
Same test on english Windows Edition run successfully.

The test :

create test.sql file that contain only "exit"

and test do :

for /l %X in (1,1,2500) do sqlplus