There is no problem. The last time your Avast attempted to update the definitions, it also updated that line of information that there is a new program update available.
Now, if you want, you can simply update manually from the main GUI of Avast.
If you don't, then in a few days the program update will be automatically performed.
If you set the program updates to "ask", then the tray notification for the program update won't appear yet. Just as I described for "automatic", some days from now the tray notification will inform you that a new program update is available (but no automatic installation with the setting in "ask").
When I say "in a few days", I don't know how many. It may be 1, or 7 or more. It depends on when exactly the program updates are "activated" for distribution in the several servers around the world.