MySQL insert binary blob don't works

We're using OTRS 4.0.6 ( www.otrs.org ) as ticketsystem.
When trying to use an attachment (JPEG Images or ZIP) in an outgoing mail, which is saved as binarys blob in the attachment table, it does not work.

OTRS log says:
Access denied for user 'ԅÜ-ªC´†�¢[É\r*\"5}4r;\Z�Ɓ�vË°.2\0…S˜?t�Ă°ÆsghuÒ!g×C^�¹[íR¯\'ŽR�k=�Aß�r†Öqg(wò{Ã�JNÑ.i4sb>ÅÌISjzL.ü4‰¯ý15?èBLÿÀ\'\"�

'@'192.168.10.50' (using password: YES), SQL: '
MySQL server has gone away, SQL:

You can try with this file: http://download.wsusoffline.net/wsusoffline951.zip

When i change the Config.pm of OTRS to use the Mysql server directly (without maxscale as loadbalancer) it works.

Unfortunately there are no other log entrys available. Neither maxscale or mysql.

Seems to me this could be some escaping problem of the binatry part of the sql query?
Dont knwo where he takes the 192.168.10.50 host from but its not our maxscale server but the otrs server itself.
Any hints?