Some of the scripts in the built __games-script.js are not minifed. So the concatenation takes both minified and original sources with comments and new lines. Here is an example:
A repro project would be good. I just tried downloading a build of the Seemore project which has a lot of scripts and it minified everything just fine.
You meant that you’ve expected your scripts to be minified in game-scripts file? Concatenation feature, only concatenates scripts, it does not modifies them (no minification is done on them).