Software updater notifications

Software updater does not seem to notify me of new updates with a pop up window. Just manually checked Thunderbird updates and there was a new update available, which was released on 23th day. I have refreshed the updater database a couple of times. Or does the notification window go away after some time, so i might miss it, if i’m away from the computer? I have the latest Avast Free. Also, i have checked the notification option from the updater.

Currently this is by design. As soon as you have multiple products which are out of date the product will no longer notify you. It assumes that you are somewhat not interested in updating and blocks the notifications.
Sorry.