This is a common problem that can be easily fixed.

Navigate to the Steam support site. Find and click on "Knockout City Trial".
If you don't see it on the list, you can search for it. It should look something like this on the top.

Now, click on the last option, which says:

Double check to make sure you are removing the trial and not the full game. Then, remove it from your library.

Now, Steam will recognize that you are playing on the full version, and all your hours and achievements will be in the right place.

I have not gotten this to work unless I re-add the trial to my library, but your results may vary.
In your browser, openThis will take you to the Steam console. In the console, enter: This is all you have to do. This will only clear achievements from the trial, not the full game, so you can safely use it to clean up your profile. If you just added it back to your library, you can follow the other steps to remove it again.