All my system messages are working fine.
When any destination that includes messages is set as Callback destination, the message file is missed:
file.c:824 ast_openstream_full: File custom/messagename does not exist in any format
I found it looks into
/var/lib/asterisk/sounds/custom
instead of
/var/lib/asterisk/sounds/it/custom
where actually all my recordings are stored.
Am I wrong with some path setting or is it a bug ?