Ionic cordova run android and plugin paths

I’m working on a ionic V3 project using a plugin with a javascript file inside: FILE.js
When I run the application on my android device (ionic cordova run android -l -c), if I make changes to the file in the plugin path nothing happens: plugins/NAMEPLUGIN/www/FILE.js
Instead, it works if I modify the file in this other path:
platforms/android/assest/www/plugin/NAMEPLUGIN/www/FILE.js

why?