This message is getting recorded in the /var/log/messages file:
TCP: Treason uncloaked! Peer 188.8.131.52:25/27430 shrinks window 3672986867:3672989475. Repaired.
This is just an informative message. It is not a problem with the system. The message is informing the system administrator that a remote system is not able to communicate correctly with the system in question. It is a problem on the remote system. It indicates that the system in question has received packets with incorrect TCP information. It is caused by a remote host, or intermediate firewall/NAT getting TCP behavior incorrectly. In the usual cases, the only likely impact is a little performance drop on the connection.
contributed by David Robinson