This was reported several times during 2011, but it was always “denied” by Avast Team members (or not answered at all).

I can confirm that the distribution spreading of new program versions is much more extended (even for months, effectively skipping some releases) than it was in the past (couple of weeks after the new release).

In all reported cases, the manual program-update was successful. The main GUI of Avast indeed displays that a new version is available, but the tray notification is delayed, sometimes for months, as well as the automatic program update.