Can't give a specific answer however a Forum Search provides many posts going back to 2017.
Here's one recent Topic of the same question.
https://forum.avast.com/index.php?topic=228945.msg1516173#msg1516173
I personally have not seen that .exe and really don't monitor processes or services by Avast as I've used Avast for over 18years and trust it. If I didn't I'd delete it and move on.
I would think that's a question best answered by Avast. 
It seems to have something to do with Windows Updater and I have an update that won't finish because it says I need to restart even though I have restarted several times, this showed up around the same time as the update, so I was thinking it's preventing the update from finishing and I'm worried I won't get updates in the future because of it.
Appologies I may have misunderstood. Thought Avast update not Windows Update.
In the past through the years if I encounter an anomaly, something that's not normal with Avast function
or updating (or I'm not sure what's going on), I resort to (If I can't run a Repair of the installation), an Uninstall.
I shut down PC. first then Reboot, and uninstall Avast via Programs and Features then also run Avastclear.exe tool; so basically a clean install. This could achieve your ability to get the update.
That's just my way of dealing with Avast glitches if I can't or don't want to figure it out.
Saves time and "for me" has resolved a lot of the unexplainable stuff with Avast or conflicting issues.
