Unable to use with usemin and no uglify step

I'm using yeoman angular project template but my usemin task has no uglify step, only concat.

Here's my config:
ngtemplates: {
dist: {
cwd: 'app',
src: 'views/{,_/}_.html',
dest: '.tmp/templateCache.js',
options: {
module: 'myApp',
usemin: 'scripts/app.js'
}
}
},
During the build the generated templateCache.js is not added to the app.js and I see this error message: Usemin has not created uglify.generated yet!

When I changed the config to this:
options: {
module: 'myApp',
concat: 'generated',
}
it works but templateCache gets added to both app.js and vendor.js.