This happens at whatever point you restart your PC as I experienced a similar update issue on number of testing machines discovered these factors to be prime reasons. You can restrict updates though in settings/downloads.
Ensure your OS isn’t old. For this windows 10 is the best viable with the updates. Steam has these update checks and bug fix appearing whenever you start your machine. It’s hard to stop them coming however you can do some adjustments at the settings menu.
Some users are annoyed by the updates and wonder what the point of so many updates is in such short intervals? With the scanty information about the updates themselves just makes them pain for the user doesn’t know what the computer is installing. Sometimes it takes hours for those updates to download and install when the number of games in the computer are numerous.
The last news about the refresh having been 2014–2016 gamers wonder are being refreshed frequently?
If you switch off updates, you risk crashes, loss of information or potentially an undermined account because of obsolete security.