It is independent of any avast update unless it changed the features/function of the webrep, it is the fact that it has to communicate with the backend servers for a) you to receive the information on the sites rep and b) to enable you to vote and for that information to be recorded on the backend servers.
As more people update to avast6 and the webrep the greater the numbers of users accessing those servers also increases. So it really is still early days and ensuring the backend servers can keep pace with the usage is always going to be a bit of a balancing act.
However, lets not loose site of the fact that currently this is a reputational tool and 'not' a part of the avast security shields as such, it isn't critical. If it is working great, use it, if not be patient.