Given that you are posting in the Beta sub-forum, I can only presume this is the recently released beta 17.4.2295 (as 17.4.2294 has been out for a while) ?
If so you are on the beta channel and program updates are handled differently (as far as I’m aware) to the regular Program Updates as they want the beta version updates to all of those on the beta channel. If you have previously used the beta version you are on the beta channel, to change that you need to download and install the current avast version 17.4.2294.