[exim] Outlook 2013 receives incorrect message

Hi,
I have an acl which rejects some messages:

deny message = This message contain spam and was rejected, if you don't agree with that please contact us (0011223344).
log_message = This message contain spam
condition = whatever

Thunderbird receive whole statement "This message contain spam and was rejected, if you don't agree with that please contact us (0011223344)" whereas Outlook 2013 receive only 20 characters from last line of message "please contact us (0".

Below tcpflow log:
x.x.x.x.00587-y.y.y.y.35189: 550-This message contain spam and was rejected, if you don't agree with that
550 please contact us (0011223344).

Have you ever seen this before ?

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Greetings
Michal