Karma opens three times in Chrome. Karma Bug?
For me, closing the browser window by pressing the X button would cause this issue to occur. There is a flag called retryLimit which is set to 2 by default, see http://karma-runner.github.io/2.0/config/configuration-file.html.
If you set that to zero, by adding the line
retryLimit : 0,somewhere in your config.set structure, the browser doesn't pop up after you close it. Though, the fact that that flag exists makes me think that you are normally supposed to close karma by some other means...
I think instead of providing the absolute path, you should set the path to chrome binary in your environmental variables.You can set it manually, or follow the instructions here: http://karma-runner.github.io/2.0/config/browsers.html