I also verified gnome-software 3.20.1+git20170524.0.ea2fe2b0-0ubuntu0.16.10.1 on Ubuntu GNOME 16.10. The logging messages stopped after reaching the search input limit.
I also verified gnome-software 3.20.1+ git20170524. 0.ea2fe2b0- 0ubuntu0. 16.10.1 on Ubuntu GNOME 16.10. The logging messages stopped after reaching the search input limit.