I have finally had it confirmed by MSN UK that they are experiencing issues with adverts that are appearing intermittently after every ‘X’ number of refreshes.

This is a system bug and hence a fairly widespread problem affecting many advertisers on the network. MSN’s tech support team are trying to address the issues currently, but this has been an issue for sometime already.

Unfortunately there is nothing advertisers can do apart from wait for the problem to be rectified…